When a discussion of neoplasms of the head and neck is initiated, the conversation frequently focuses on squamous cell carcinoma. This is because the majority of malignancies of this region are represented by this pathology. The diagnosis and treatment of lesions spanning from the lips and oral cavity to the larynx and hypopharynx requires a similar methodic approach.
The selection of treatment protocols varies for each site within the upper aerodigestive tract. The importance of multidisciplinary management cannot be underestimated. Presentation of cases before a tumor board allowing review of a patient’s history, physical examination findings, imaging, and prior pathology specimens allows for confirmation of the patient’s status. Additionally, it should encourage discussion from multiple points of view concerning the most appropriate treatment options available. Participation in the discussion with representatives of radiation oncology, medical oncology, surgical oncology, oral maxillofacial surgery/dental medicine, along with radiologists and pathologists specializing in upper aerodigestive tract disorders benefits not only the patient but also represents an excellent teaching opportunity for all disciplines.
The development of organ preservation protocol and the evolution of free tissue reconstructive techniques are some of the most significant advances made within the field during the last two decades. The future of the treatment of head and neck cancer lies within the field of molecular biology. As more is understood about the genetics of cancer, tailoring treatment options to a particular tumor mutation has the capacity to maximize survival while achieving the highest quality of life.
Etiology and Epidemiology
It should come as no surprise that abuse of tobacco and alcohol are the most common preventable risk factors associated with the development of head and neck cancers. This relationship is synergistic rather than additive. Smoking confers a 1.9-fold increased risk to males and a threefold increased risk to females for developing a head and neck carcinoma, compared to nonsmokers. The risk increases as the number of years smoking and number of cigarettes smoked per day increases. Alcohol alone confers a 1.7-fold increased risk to males drinking one to two drinks per day, compared to nondrinkers. This increased risk rises to > threefold for heavy drinkers. Individuals who both smoke (two packs per day) and drink (four units of alcohol per day) had a 35-fold increased risk for the development of a carcinoma compared to controls.36 Users of smokeless tobacco have a four times increased risk of oral cavity carcinoma compared to nonusers.
Tobacco is the leading preventable cause of death in the United States and is responsible for one of every five deaths.37Approximately one fourth of U.S. adults habitually use tobacco products, with recent trends demonstrating an increase in the use of tobacco products by women. The evidence supporting the need for head and neck cancer patients to pursue smoking cessation after treatment is compelling. In a study by Moore, 40% of patients who continued to smoke after definitive treatment for an oral cavity malignancy went on to recur or develop a second head and neck malignancy.38 For patients who stopped smoking after treatment, only 6% went on to develop a recurrence. Induction of specific p53 mutations within upper aerodigestive tract tumors has been noted in patients with histories of tobacco and alcohol use.39,40
When smokers who develop head and neck squamous cell carcinomas are compared to nonsmokers, differences between the two populations emerge. Koch and associates41 noted that nonsmokers were represented by a disproportionate number of women and were more frequently at the extremes of age (<30 or >85 years of age). Tumors from nonsmokers presented more frequently in the oral cavity, specifically within the oral tongue, buccal mucosa, and alveolar ridge. Smokers presented more frequently with tumors of the larynx, hypopharynx, and floor of mouth. Former smokers, defined as those individuals who had quit >10 years prior, demonstrated a profile more consistent with nonsmokers.
In India and Southeast Asia, the product of the areca catechu tree, known as a betel nut, is chewed in a habitual manner and acts as a mild stimulant similar to that of coffee. The nut is chewed in combination with lime and cured tobacco as a mixture known as a quid. The long-term use of the betel nut quid can be destructive to oral mucosa and dentition and is highly carcinogenic.42 Another habit associated with oral malignancy is that of reverse smoking, where the lighted portion of the tobacco product is within the mouth during inhalation. The risk of hard palate carcinoma is 47 times greater in reverse smokers compared to nonsmokers.
HPV is an epitheliotropic virus that has been detected to various degrees within samples of oral cavity squamous cell carcinoma. Infection alone is not considered sufficient for malignant conversion; however, results of multiple studies suggest a role of HPV in a subset of head and neck squamous cell carcinoma. Multiple reports reflect that up to 40% to 60% of current diagnoses of tonsillar carcinoma demonstrate evidence of HPV types 16 or 18.
Environmental ultraviolet light exposure has been associated with the development of lip cancer. The projection of the lower lip, as it relates to this solar exposure, has been used to explain why the majority of squamous cell carcinomas arise along the vermilion border of the lower lip. In addition, pipe smoking also has been associated with the development of lip carcinoma. Factors such as mechanical irritation, thermal injury, and chemical exposure have been described as an explanation for this finding.
Other entities associated with oral malignancy include Plummer-Vinson syndrome (achlorhydria, iron-deficiency anemia, mucosal atrophy of mouth, pharynx, and esophagus), chronic infection with syphilis, and immunocompromised status (30-fold increase with renal transplant).
Although evidence linking HIV infection to squamous cell carcinoma of the head and neck is lacking, several AIDS-defining malignancies, including Kaposi’s sarcoma, and non-Hodgkin’s lymphoma may require the care of an otolaryngologist.
Anatomy and Histopathology
The upper aerodigestive tract is divided into several distinct sites that include the oral cavity, pharynx, larynx, and nasal cavity/paranasal sinuses. Within these sites are individual subsites with specific anatomic relationships that affect diagnosis, tumor spread, and selection of treatment options. The spread of a tumor from one site to another is determined by the course of the nerves, blood vessels, lymphatic pathways, and fascial planes. The fascial planes serve as barriers to the direct invasion of tumor and facilitate the pattern of spread to regional lymph nodes.
The oral cavity extends from the vermilion border of the lip to the hard-palate/soft-palate junction superiorly, to circumvallate papillae inferiorly, and to the anterior tonsillar pillars laterally (Fig. 18-19). It is divided into seven subsites: lips, alveolar ridges, oral tongue, retromolar trigone, floor of mouth, buccal mucosa, and hard palate. Advanced oral cavity lesions may present with mandibular and/or maxillary involvement requiring special consideration at the time of resection and reconstruction. Regional metastatic spread of lesions of the oral cavity is to the lymphatics of the submandibular and the upper jugular region (e.g., levels I, II, and III).
The pharynx is divided into three regions: nasopharynx, oropharynx, and hypopharynx. The nasopharynx extends from the posterior nasal septum and choana to the skull base and includes the fossa of Rosenmüller and torus tubarius of the Eustachian tubes laterally. The inferior margin of the nasopharynx is the superior surface of the soft palate. The adenoids, typically involuted in adults, are located with the posterior aspect of this site. Given the midline location of the nasopharynx, bilateral regional metastatic spread is common in these lesions. Lymphadenopathy of the posterior triangle (level V) of the neck should provoke consideration for a nasopharyngeal primary.
The major sites within the oropharynx are the tonsillar region, base of tongue, soft palate, and posterolateral pharyngeal walls. Regional lymphatic drainage for oropharyngeal lesions frequently occurs to the upper and lower cervical lymphatics (e.g., levels II, III, IV). Retropharyngeal metastatic lymphatic spread may occur with oropharyngeal lesions.
The hypopharynx extends from the vallecula to the lower border of the cricoid posterior and lateral to the larynx. The subsites of this region include the pyriform fossa, the postcricoid space, and posterior pharyngeal wall. Regional lymphatic spread is frequently bilateral and to the mid- and lower cervical lymph nodes (e.g., levels III, IV).
The larynx is divided into three regions: the supraglottis, glottis, and subglottis. The supraglottic larynx includes the epiglottis, false vocal cords, medial surface of the aryepiglottic folds, and the roof of the laryngeal ventricles. The glottis includes the true vocal cords, anterior and posterior commissure, and the floor of the laryngeal ventricle. The subglottis extends from below the true vocal cords to the cephalic border of the cricoid within the airway. The supraglottis has a rich lymphatic network, which accounts for the high rate of bilateral spread of metastatic disease that is not typically seen with the glottis. Glottic and subglottic lesions, in addition to potential spread to the cervical chain lymph nodes, may also spread to the paralaryngeal and paratracheal lymphatics and require attention to prevent lower central neck recurrence.
Development of a tumor represents the loss of cellular signaling mechanisms involved in the regulation of growth. Following malignant transformation, the processes of replication (mitosis), programmed cell death (apoptosis), and the interaction of a cell with its surrounding environment are altered. Advances in molecular biology have allowed for the identification of many of the mutations associated with this transformation.
Overexpression of mutant p53 is associated with carcinogenesis at multiple sites within the body. Point mutations in p53 have been reported in up to 45% of head and neck carcinomas. Koch et al noted that p53 mutation is a key event in the malignant transformation of >50% of head and neck squamous cell carcinomas in smokers.41
Carcinogenesis has long been explained as a two-hit process, involving DNA damage and the progression of mutated cells through the cell cycle. These two events also are known as initiation and promotion. It has been proposed that approximately 6 to 10 independent genetic mutations are required for the development of a malignancy. Overexpression of mitogenic receptors, loss of tumor-suppressor proteins, expression of oncogene-derived proteins that inhibit apoptosis, and overexpression of proteins that drive the cell cycle can allow for unregulated cell growth.
Genetic mutations may occur as a result of environmental exposure (e.g., radiation or carcinogen exposure), viral infection, or spontaneous mutation (deletions, translocations, frame shifts). Common genetic alterations, such as loss of heterozygosity at 3p, 4q, and 11q13, and the overall number of chromosomal microsatellite losses are found more frequently in the tumors of smokers than in the tumors of nonsmokers.41
Second Primary Tumors in the Head and Neck
Patients diagnosed with a head and neck cancer are predisposed to the development of a second tumor within the aerodigestive tract. The overall rate of second primary tumors is approximately 14%. A second primary tumor detected within 6 months of the diagnosis of the initial primary lesion is defined as a synchronous neoplasm. The prevalence of synchronous tumors is approximately 3% to 4%. The detection of a second primary lesion more than 6 months after the initial diagnosis is referred to as metachronous tumor. About 80% of second primaries are metachronous and at least half of these lesions develop within 2 years of the diagnosis of the original primary. The incidence and site of the second primary tumor vary and depend on the site and the inciting factors associated with the initial primary tumor. The importance of advocating smoking cessation and addressing alcoholism in these patients cannot be overemphasized.
Patients with a primary malignancy of the oral cavity or pharynx are most likely to develop a second lesion within the cervical esophagus, whereas patients with a carcinoma of the larynx are at risk for developing a neoplasm in the lung. As such, the presentation of a new-onset dysphagia, unexplained weight loss, or chronic cough/hemoptysis must be assessed thoroughly in patients with a history of prior treatment for a head and neck cancer.
A staging examination is recommended at the initial evaluation of all patients with primary cancers of the upper aerodigestive tract. This may involve a direct laryngoscopy, rigid/flexible esophagoscopy, and rigid/flexible bronchoscopy also known as “panendoscopy.” Some surgeons argue against the use of bronchoscopy because of the low yield of the examination in asymptomatic patients with a normal chest X-ray. Additionally, barium swallow has been used instead of esophagoscopy as a preoperative evaluation.
Staging for upper aerodigestive tract malignancies is defined by the American Joint Committee on Cancer and follows the TNM (primary tumor, regional nodal metastases, distant metastasis) staging format43. The T staging criteria for each site varies depending upon the relevant anatomy (e.g., vocal cord immobility is seen with T3 lesions). Table 18-1 demonstrates TNM staging for oral cavity lesions. The N classification system is uniform for all head and neck sites except for the nasopharynx.
Table 18-1TNM staging for oral cavity carcinoma ||Download (.pdf) Table 18-1 TNM staging for oral cavity carcinoma
|Primary Tumor |
|TX ||Unable to assess primary tumor || || |
|T0 ||No evidence of primary tumor || || |
|Tis ||Carcinoma in situ || || |
|T1 ||Tumor is < 2 cm in greatest dimension || || |
|T2 ||Tumor > 2 cm and < 4 cm in greatest dimension || || |
|T3 ||Tumor > 4 cm in greatest dimension || || |
|T4 (lip) ||Primary tumor invading cortical bone, inferior alveolar nerve, floor of mouth, or skin of face (e.g., nose or chin) || || |
|T4a (oral) ||Tumor invades adjacent structures (e.g., cortical bone, into deep tongue musculature, maxillary sinus) or skin of face || || |
|T4b (oral) ||Tumor invades masticator space, pterygoid plates, or skull base and/or encases the internal carotid artery || || |
|Regional lymphadenopathy |
|NX ||Unable to assess regional lymph nodes || || |
|N0 ||No evidence of regional metastasis || || |
|N1 ||Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension || || |
|N2a ||Metastasis in single ipsilateral lymph node, >3 cm and < 6 cm || || |
|N2b ||Metastasis in multiple ipsilateral lymph nodes, all nodes < 6 cm || || |
|N2c ||Metastasis in bilateral or contralateral lymph nodes, all nodes < 6 cm || || |
|N3 ||Metastasis in a lymph node > 6 cm in greatest dimension || || |
|Distant metastases |
|MX ||Unable to assess for distant metastases || || |
|M0 ||No distant metastases || || |
|M1 ||Distant metastases || || |
|TMN Staging || || || |
|Stage 0 ||Tis ||N0 ||M0 |
|Stage I ||T1 ||N0 ||M0 |
|Stage II ||T2 ||N0 ||M0 |
|Stage III ||T3 ||N0 ||M0 |
| ||T1-3 ||N1 ||M0 |
|Stage IVa ||T4a ||N0 ||M0 |
| ||T4a ||N1 ||M0 |
| ||T1-4a ||N2 ||M0 |
|Stage IVb ||Any T ||N3 ||M0 |
| ||T4b ||Any N ||M0 |
|Stage IVc ||Any T ||Any N ||M1 |
Upper Aerodigestive Tract
The lips represent a transition from external skin to internal mucous membrane that occurs at the vermilion border. The underlying musculature of the orbicularis oris creates a circumferential ring that allows the mouth to have a sphincter-like function. Cancer of the lip is most commonly seen in white men from the ages of 50 to 70 years, but can be seen in younger patients, particularly those with fair complexions. Risk factors include prolonged exposure to sunlight, fair complexion, immunosuppression, and tobacco use.
The majority of lip malignancies are diagnosed on the lower lip (88%–98%), followed by the upper lip (2%–7%) and oral commissure (1%). The histology of lip cancers is predominantly squamous cell carcinoma; however, other tumors, such as keratoacanthoma, verrucous carcinoma, basal cell carcinoma, malignant melanoma, minor salivary gland malignancies, and tumors of mesenchymal origin (e.g., malignant fibrous histiocytoma, leiomyosarcoma, and rhabdomyosarcoma), may also present in this location. Basal cell carcinoma presents more frequently on the upper lip than lower.
Clinical findings in lip cancer include an ulcerated lesion on the vermilion or cutaneous surface. Careful palpation is important in determining the actual size and extent of these lesions. The presence of paresthesia in the area adjacent to the lesion may indicate mental nerve involvement.
Characteristics of lip primaries that negatively affect prognosis include perineural invasion, involvement of the underlying maxilla/mandible, presentation on the upper lip or commissure, regional lymphatic metastasis, and age younger than 40 years at onset. Lip cancer results in fewer than 200 patient deaths annually and is stage dependent. Early diagnosis coupled with adequate treatment results in a high likelihood of disease control.
The selection of treatment for any given lip cancer is determined by the overall health of the patient, size of the primary lesion, and the presence of regional metastases. Small primary lesions may be treated with surgery or radiation with equal success and acceptable cosmetic results. However, surgical excision with histologic confirmation of tumor-free margins is the preferred treatment modality. Lymph node metastasis occurs in fewer than 10% of patients with lip cancer (Fig. 18-20). The primary echelon of nodes at risk is in the submandibular and submental regions. In the presence of clinically evident neck metastasis, neck dissection is indicated. The overall 5-year cure rate of lip cancer approximates 90% and drops to 50% in the presence of neck metastases. Postoperative radiation is administered to the primary site and neck for patients with close or positive margins, lymph node metastases, when tumor thickness is >4mm or in the setting of perineural invasion.44
The reconstruction of lip defects after tumor excision requires innovative techniques to provide oral competence, maintenance of dynamic function, and acceptable cosmesis. The typical lip length is 6 to 7 cm. This simple fact is important because the reconstructive algorithms available to the head and neck surgeon are based on the proportion of lip resected. Realignment of the vermilion border during the reconstruction and preservation of the oral commissure (when possible) are important principles in attempting to attain an acceptable cosmetic result. Resection with primary closure is possible with a defect of up to one third of the lip (Fig. 18-21). When the resection includes one third to one half of the lip, rectangular excisions can be closed using Burow’s triangles in combination with advancement flaps and releasing incisions in the mental crease.45 Rotational transposition of tissue from the upper lip can repair other medium-size defects. For larger defects of up to 75%, the Karapandzic flap uses a sensate, neuromuscular flap that includes the remaining orbicularis oris muscle, conserving its blood supply from branches of the labial artery (Fig. 18-22). The lip-switch (Abbe-Estlander) flap or a stair-step advancement technique can be used to repair defects of either the upper or lower lip. Microstomia is a potential complication with these types of lip reconstruction. For very large defects, Webster or Bernard types of repair using lateral nasolabial flaps with buccal advancement have also been described.46
Wedge resection of lower lip squamous cell carcinoma.
A-C. Karapandzic labiaplasty for lower lip carcinoma.
As previously mentioned in Anatomy and Histopathology, the oral cavity is composed of several sites with different anatomic relationships. The majority of tumors in the oral cavity are squamous cell carcinomas (>90%). Each site is briefly reviewed with emphasis placed on anatomy, diagnosis, and treatment options.
The oral tongue is a muscular structure with overlying nonkeratinizing squamous epithelium. The posterior limit of the oral tongue is the circumvallate papillae, whereas its ventral portion is contiguous with the anterior floor of mouth. The tongue is composed of four intrinsic and four extrinsic muscles separated at the midline by the median fibrous septum. Tumors of the tongue begin in the stratified epithelium of the surface and eventually invade into the deeper muscular structures. The tumors may present as ulcerations or as exophytic masses (Fig. 18-23).47 The regional lymphatics of the oral cavity are to the submandibular space and the upper cervical lymph nodes (Fig. 18-24). The lingual nerve and the hypoglossal nerve may be directly invaded by locally extensive tumors (Fig. 18-25). Involvement can result in ipsilateral paresthesias and deviation of the tongue on protrusion with fasciculations and eventual atrophy. Tumors on the tongue may occur on any surface, but are most commonly seen on the lateral and ventral surfaces.48 Primary tumors of the mesenchymal components of the tongue include leiomyomas, leiomyosarcomas, rhabdomyosarcomas, and neurofibromas.
Oral tongue squamous cell carcinoma.
Primary lymphatics for regional spread of oral cavity malignancies.
A and B. Anatomy of the floor of mouth and submandibular space. a. = artery; m. = muscle; n. = nerve.
Surgical treatment of small (T1–T2) primary tumors is wide local excision with either primary closure or healing by secondary intention. The CO2 laser may be used for excision of early tongue cancers or for ablation of premalignant lesions. A partial glossectomy, which removes a significant portion of the lateral oral tongue, still permits reasonably effective postoperative function. Resection of larger tumors of the tongue that invade deeply can result in significant functional impairment. If lingual contact with the palate, lip, and teeth is decreased, it will result in impaired articulation. The use of soft, pliable fasciocutaneous free flaps can provide intraoral bulk and preservation of tongue mobility. Prosthetic augmentation can allow for contact between the remaining tongue tissue and the palate, improving a patient’s ability to speak and swallow. Treatment of the regional lymphatics is typically performed with the same modality used to address the primary site. When the primary site is addressed surgically, modified radical neck dissection (MRND) or selective neck dissection (SND) is performed. Depth of invasion of the primary tumor can direct the need for elective lymph node dissection with early stage lesions.49
The floor of mouth is a mucosal covered semilunar area that extends from the anterior tonsillar pillar posteriorly to the frenulum anteriorly, and from the inner surface of the mandible to the ventral surface of the oral tongue. The ostia of the submaxillary and sublingual glands are contained in the anterior floor of mouth. The muscular floor of mouth is composed of the sling-like genioglossus, mylohyoid, and hyoglossus muscles, which serve as a barrier to spread of disease. Invasion into these muscles can result in decreased tongue mobility and poor articulation. Another pathway for spread of tumor is along the salivary ducts, which can result in direct extension into the sublingual space.
Anterior or lateral extension to the mandibular periosteum is of primary importance in the preoperative assessment for these lesions. Imaging studies of the mandible, including CT scan, magnetic resonance imaging (MRI), and Panorex radiography, are helpful for ascertaining bone invasion. A careful clinical evaluation, which includes bimanual palpation to assess adherence or fixation to adjacent bone, is also essential (Fig. 18-26). The absence of fixation of the lesion to the inner mandibular cortex indicates that a mandible-sparing procedure is feasible.50 Deep invasion into the intrinsic musculature of the tongue causes fixation and mandates a partial glossectomy in conjunction with resection of the floor of mouth. Lesions in the anterior floor of mouth may invade the sublingual gland or submandibular duct and require resection of either of these structures in continuity with the primary lesion. Direct extension of tumors into or through the sublingual space and into the submaxillary space may necessitate the need for removal of the primary tumor with the neck dissection specimen in continuity.
A and B. Differences in the transoral resection of a floor of mouth and alveolar ridge lesion.
The resection of large tumors of the floor of mouth may require a lip-splitting incision (Fig. 18-27) and immediate reconstruction. The goals are to obtain watertight closure to avoid a salivary fistula and to avoid tongue tethering to maximize mobility. For small mucosal lesions, wide local excision can be followed by placement of a split-thickness skin graft over the muscular bed. Larger defects that require marginal or segmental mandibulectomy require complex reconstruction with a fasciocutaneous or a vascularized osseous free flap.
Composite resection specimen of a T4 floor of mouth squamous cell carcinoma.
The alveolar mucosa overlies the bone of the mandible and maxilla. It extends from the gingivobuccal sulcus to the mucosa of the floor of mouth and hard palate. The posterior limits are the pterygopalatine arch and the ascending portion of the ramus of the mandible. Because of the tight attachment of the alveolar mucosa to the mandibular and maxillary periosteum, treatment of lesions of the alveolar mucosa frequently requires resection of the underlying bone.
Marginal resection of the mandible can be performed for tumors of the alveolar surface that present with minimal bone invasion. Although access for such a procedure can be performed by using an anterior mandibulotomy (Fig. 18-28), use of transoral and pull-through procedures is preferred if a coronal or sagittal marginal mandibulotomy is performed. For more extensive tumors that invade into the medullary cavity, segmental mandibulectomy is necessary. Preoperative radiographic evaluation of the mandible plays an important role in determining the type of bone resection required. For radiographic evaluation of the mandible, Panorex views demonstrate gross cortical invasion. MRI is the best modality for demonstrating invasion of the medullary cavity of the mandible. Sectional CT scanning with bone settings is the optimum modality for imaging subtle cortical invasion. Gross bony invasion involvement at the mandibular symphysis negatively impacts locoregional control.51
Anterior mandibulotomy with mandibular swing to approach a posterior lesion.
The retromolar trigone is represented by tissue posterior to the posterior inferior alveolar ridge and ascends over the inner surface of the ramus of the mandible. Similar to alveolar lesions, early involvement of the mandible is common because of the lack of intervening soft tissue in the region. The clinical presentation of trismus represents involvement of the muscles of mastication and may indicate spread to the skull base. Tumors of the region may extend posteriorly into the oropharyngeal anatomy or laterally to invade the mandible. As a result, resection of retromolar trigone tumors usually requires a marginal or segmental mandibulectomy with a soft-tissue and/or osseous reconstruction to maximize a patient’s postoperative ability for speech and swallowing. Ipsilateral neck dissection is performed because of the risk of metastasis to the regional lymphatics. Huang and associates demonstrated a 5-year, disease-free survival rate for T1 lesions of 76%, which declined to 54% for T4 disease. Patients with N0 disease had a 5-year survival rate of 69%.52
The buccal mucosa includes all of the mucosal lining from the inner surface of the lips to the line of attachment of mucosa of the alveolar ridges and pterygomandibular raphe. The etiologies of malignancies in the buccal area include lichen planus, chronic dental trauma, and the habitual use of tobacco and alcohol. Tumors in this area have a propensity to spread locally and to metastasize to regional lymphatics. Local intraoral spread may necessitate resection of the alveolar ridge of the mandible or maxilla. Lymphatic drainage is to the facial and the submandibular nodes (level I). Small lesions can be excised surgically, but more advanced tumors require combined surgery and postoperative radiation.53 Deep invasion into the cheek may require through-and-through resection. Reconstruction aimed at providing both an internal and external lining may be accomplished with a folded fasciocutaneous free flap or a combination of pedicled and free tissue techniques.
The hard palate is defined as the semilunar area between the upper alveolar ridge and the mucous membrane covering the palatine process of the maxillary palatine bones. It extends from the inner surface of the superior alveolar ridge to the posterior edge of the palatine bone. Most squamous cell carcinomas of the hard palate are caused by habitual tobacco and alcohol use. Chronic irritation from ill-fitting dentures also may play a causal role. Inflammatory lesions arising on the palate may mimic malignancy and can be differentiated by biopsy specimen. Necrotizing sialometaplasia appears on the palate as a butterflyshaped ulcer that clinically appears similar to a neoplasm. Treatment is symptomatic and biopsy specimen confirms its benign nature. Torus palatini are bony outgrowths of the midline palate and do not specifically require surgical treatment unless symptomatic.
Squamous cell carcinoma and minor salivary gland tumors are the most common malignancies of the palate.54 The latter include adenoid cystic carcinoma, mucoepidermoid carcinoma, adenocarcinoma, and polymorphous low-grade adenocarcinoma. Mucosal melanoma may occur on the palate and presents as a nonulcerated, pigmented plaque. Kaposi’s sarcoma of the palate is the most common intraoral site for this tumor. Tumors may present as either an ulcerative, exophytic, or submucosal mass. Minor salivary gland tumors tend to arise at the junction of the hard and soft palate. Direct infiltration of bone leads to extension into the floor of the nasal cavity and/or maxillary sinus. Squamous cell carcinoma of the hard palate is treated surgically. Adjuvant radiation is indicated for advanced staged tumors. Because the periosteum of the palate can act as a barrier to spread of tumor, mucosal excision may be adequate for very superficial lesions. Involvement of the periosteum requires removal of a portion of the bony palate. Partial palatectomy of infrastructure maxillectomy may be required for larger lesions involving the palate or maxillary antrum. Malignancies may extend along the greater palatine nerve making biopsy specimen important for identifying neurotropic spread. Through-and-through defects of the palate require a dental prosthesis for rehabilitation of swallowing and speech.
The oropharynx extends from the soft palate to the superior surface of the hyoid bone (or floor of the vallecula) and includes the base of tongue, the inferior surface of the soft palate and uvula, the anterior and posterior tonsillar pillars, the glossotonsillar sulci, tonsils, and the lateral and posterior pharyngeal walls. Laterally, the borders of this region are the pharyngeal constrictors and the medial aspect of the mandible. Direct extension of tumors from the oropharynx into these lateral tissues may involve spread into the parapharyngeal space. The ascending ramus of the mandible can be involved when tumors invade the medial pterygoid muscle.
As was true of the oral cavity, the histology of the majority of tumors in this region is squamous cell carcinoma. Although less common, minor salivary gland tumors may present as submucosal masses in the tongue base and soft palate. Additionally, the tonsils and tongue base may be the presenting site for a lymphoma noted clinically as asymmetrical enlargement.
Oropharyngeal cancer may present as an ulcerative lesion or an exophytic mass. Tumor fetor from necrosis is common. A muffled or “hot potato” voice is seen with large tongue base tumors. Dysphagia and weight loss are common symptoms. Referred otalgia, mediated by the tympanic branches of cranial nerve (CN) IX and CN X, is a common complaint. Trismus may indicate advanced disease and usually results from involvement of the pterygoid musculature. The incidence of regional metastases from cancers of the oropharynx is high. Consequently, ipsilateral or bilateral nontender cervical lymphadenopathy is a common presenting sign.
The incidence of oropharyngeal squamous cell carcinoma has increased significantly over the last three decades. The etiology for this rise has been attributed to the HPV-16 related development of malignancy. HPV infection can induce the production of two viral oncoproteins, E6 and E7, which inactivate tumor suppressors p53 and Rb leading to tumor promotion. In a prospective clinical trial of patients enrolled in the Eastern Cooperative Group (ECOG) trial 2399, Fakhry et al reported on the survival benefit seen in oropharyngeal cancer patients that were HPV-positive. Patients were treated with sequential chemoradiation for advanced stage disease. HPV positivity was found in 57% of all oropharyngeal cancers in the study. HPV-positive cancers demonstrated a higher response rate to induction chemotherapy (82% vs. 55%) and improved 2-year survival (95% vs. 62%). Compared to patients with HPV-negative tumors, HPV-positive cancers presented in younger male patients and were associated with a history of higher lifetime number of sexual partners and oral sex.55 HPV-associated oropharyngeal carcinoma is considered to represents a distinct clinicopathologic entity different from the traditional squamous cell carcinoma of the head and neck associated with the long-term use of tobacco and alcohol (Table 18-2). Surprisingly, the rate of distant metastasis is similar in HPV-positive and HPV-negative patients indicating survival benefits are likely from improved locoregional control with treatment. Clinical trials are currently being performed to assess if therapy can be deintensified in the HPV patient population while obtaining the same locoregional and overall survival seen with standard treatment options.
Table 18-2Head and neck squamous cell carcinoma patterns of presentation ||Download (.pdf) Table 18-2 Head and neck squamous cell carcinoma patterns of presentation
|VARIABLE ||HPV-POSITIVE ||HPV-NEGATIVE |
|Typical age ||40 – 60 years ||over 60 years of age |
|Primary site ||tongue base, tonsil ||entire UADT |
|Prognosis with ASD ||favorable ||poor |
|Risk factors ||oral sex, number of partners ||habitual tobacco and alcohol use |
|Incidence ||increasing ||stable, decreasing |
Imaging studies are important for adequate staging and should assess for extension to the larynx, parapharyngeal space, pterygoid musculature, mandible, and nasopharynx. Lymph node metastasis from oropharyngeal cancer most commonly occurs in the subdigastric area of level II. Metastases also are found in levels III, IV, and V, in addition to the retropharyngeal and parapharyngeal lymph nodes. Approximately 50% of patients have metastases at the time of presentation and bilateral metastases are common from tumors arising in the tongue base and soft palate.
The treatment goals for patients with oropharyngeal cancer include maximizing survival and preserving function. Management of squamous cell cancers of this region includes surgery alone, primary radiation alone, surgery with postoperative radiation, and combined chemotherapy with radiation therapy.56 Tumors of the oropharynx tend to be radiosensitive.57 Patients with early stage lesions may be candidates for monomodality radiation alone. Adequate treatment of the neck is important with oropharyngeal squamous cancer because of the high risk of regional metastasis. Concomitant chemoradiation is commonly utilized in patients with advanced stage (III, IV) oropharyngeal carcinoma.58 This approach has been effectively demonstrated to preserve function and is associated with survivorship comparable to surgery with postoperative radiation.
In an effort to resect tumors of the oropharynx in a minimally invasive fashion, that might otherwise require a lip-splitting mandibulotomy approach with dissection through the floor of mouth, the transoral robotic surgical approach utilizing the da Vinci Surgical System has been utilized with favorable results. Dean et al reported on the use of robot-assisted primary and salvage surgery for 36 patients with T1 and T2 tumors of the oropharynx compared to traditional open salvage resection. Patients that underwent robot-assisted surgery had shorter lengths of stay and were less likely to be gastrostomy tube or tracheostomy dependent at 6 months.59 Of patients undergoing primary transoral robotic surgery to tonsillar carcinoma, 93% still required some form of postoperative adjuvant therapy.60 Advocates of the technique believe that initial surgical management of the oropharynx, a site typically treated with primary radiation or chemoradiation therapy, allows for a better long-term functional result with the potential for decreasing the intensity of adjuvant therapy to radiation alone as opposed to postoperative chemoradiation. Clinical trials and experience with the technique and continue evolve with the focus of use directed at early-stage oropharyngeal carcinomas.
Extensive oropharyngeal cancers may require surgical resection and postoperative radiotherapy. Lesions that involve the mandible require composite resections, such as the classic jaw-neck resection or “commando” procedure. Surgical management of the tongue base may require total glossectomy for extensive lesions crossing the anatomic midline. The potential need for synchronous performance of total laryngectomy at the time of tongue base resection should be explained to the patient. Preservation of the larynx after total glossectomy is associated with a significant risk of postoperative dysphagia and aspiration.61
Swallowing rehabilitation in patients with oropharyngeal carcinoma is an important aspect of posttreatment care. For soft palate defects, palatal obturators may assist in providing a seal between the nasopharynx and the posterior pharyngeal wall. Nasal regurgitation of air and liquids can be decreased with use. Close cooperation between the head and neck surgeon and the maxillofacial prosthodontist is essential to provide patients with the optimum prosthetic rehabilitation. Preoperative planning can result in the creation of a defect that better tolerates obturation. For patients with postglossectomy defects, palatal augmentation prostheses can provide bulk extending inferiorly from the palate. The prosthesis decreases the volume of the oral cavity and allows the remaining tongue or soft tissue to articulate with the palate. It also facilitates posterior projection of the food bolus during the oral and pharyngeal phases of swallowing.
Hypopharynx and Cervical Esophagus
The hypopharynx extends from the vallecula to the lower border of the cricoid cartilage and includes the pyriform sinuses, the lateral and posterior pharyngeal walls, and the postcricoid region (Fig. 18-29). Squamous cancers of the hypopharynx frequently present at an advanced stage. Clinical findings are similar to those of lower oropharyngeal lesions and include a neck mass, muffled or hoarse voice, referred otalgia, dysphagia, and weight loss. A common symptom is dysphagia, starting with solids and progressing to liquids, leaving patients malnourished at the time of presentation. Invasion of the larynx by direct extension can result in vocal cord paralysis and may lead to airway compromise.
Relationship of nasopharynx, oropharynx, and hypopharynx.
Routine office examination should include flexible fiber-optic laryngoscopy to properly assess the extent of tumor. During examination, the patient should be instructed to perform a Valsalva maneuver, which will result in passive opening of the pyriform sinuses and postcricoid regions, providing improved visualization. Decreased laryngeal mobility or fixation may indicate invasion of the prevertebral fascia and unresectability. Barium swallow can provide information regarding postcricoid and upper esophageal extension, potential multifocality within the esophagus, and document the presence of aspiration. CT and/or MRI imaging should be obtained through the neck and upper chest to assess for invasion of the laryngeal framework and to identify for regional metastases, with special attention given to the paratracheal and upper mediastinal lymph nodes (Fig. 18-30). Bilateral metastatic adenopathy in the paratracheal chain is common and the majority of patients present with nodal disease at the time of diagnosis.
View of the hypopharynx demonstrating the potential pathways of spread of tumor and pertinent anatomy.
Tumors of the hypopharynx and cervical esophagus are associated with poorer survival rates than are other sites in the head and neck because of advanced stage and lymph node metastasis at presentation. Surgery with postoperative radiation therapy improves locoregional control compared to single-modality therapy in the treatment of advanced stage tumors.62 Definitive radiation therapy may be effective for limited T1 tumors, whereas concomitant chemoradiation is generally used for T2 and T3 tumors.63 Surgical salvage after radiation failure has a success rate of less than 50% and can be associated with significant wound-healing complications.
Larynx-preserving surgical procedures for tumors of the hypopharynx are possible for only a limited number of lesions. Tumors of the medial pyriform wall or pharyngo-epiglottic fold may be resected with partial laryngopharyngectomy. In this circumstance, the tumor must not involve the apex of the pyriform sinus, vocal cord mobility must be unimpaired, and the patient must have adequate pulmonary reserve. Given the increased risk for postoperative aspiration associated with various forms of partial laryngectomy, a history significant for pulmonary disease is a contraindication for performing the procedures. Because the majority of patients with tumors of the hypopharynx present with large lesions with significant submucosal spread, total laryngectomy often is required to achieve negative resection margins. Resection of the primary tumor and surrounding pharyngeal tissue is performed en bloc. Bilateral neck dissection is frequently indicated given the elevated risk of nodal metastases found with these lesions.
When laryngopharyngectomy is performed for hypopharyngeal tumors the surgical defect is repaired by primary closure when possible. Generally, 4 cm or more of pharyngeal mucosa is necessary for primary closure to provide an adequate lumen for swallowing and to minimize the risk of stricture formation. Larger surgical defects require closure with the aid of pedicled myocutaneous flaps or microvascular reconstruction with radial forearm or jejunal free flap. When total laryngopharyngoesophagectomy is necessary, gastric pull-up is performed.
Cervical esophageal cancer may be managed surgically or by concomitant chemoradiation. Preservation of the larynx is possible if the cricopharyngeus muscle demonstrates limited involvement. Unfortunately, this is not often the case and many patients with cervical esophageal cancer require laryngectomy. Total esophagectomy is performed because of the tendency for multiple primary tumors and skip lesions seen with esophageal cancers.
Despite aggressive treatment strategies, the 5-year survival rate for cervical esophageal cancer is less than 20%. Given the presence of paratracheal lymphatic spread, surgical treatment for tumors of this area must include paratracheal lymph node dissection, in addition to treatment of the lateral cervical lymphatics.
Laryngeal carcinoma is a diagnosis typically entertained in individuals with prominent smoking histories and the complaint of a change in vocal quality (Fig. 18-31). The borders of the larynx span from the epiglottis superiorly to the cricoid cartilage inferiorly. The lateral limits of the larynx are the aryepiglottic folds. The larynx is composed of three regions: the supraglottis, the glottis, and the subglottic (Fig. 18-32).
Endoscopic view of a laryngeal squamous carcinoma.
Sagittal view of the larynx with the divisions of the supraglottis, glottis, and subglottis demonstrated.
The supraglottic includes the epiglottis, aryepiglottic folds, arytenoids, and ventricular bands (false vocal folds). The inferior boundary of the supraglottic is a horizontal plane passing through the lateral margin of the ventricle. The glottis is composed of the true vocal cords (superior and inferior surfaces) and includes the anterior and posterior commissures. The subglottic extends from the inferior surface of the glottis to the lower margin of the cricoid cartilage. The soft-tissue compartments of the larynx are separated by fibroelastic membranes, which can act as barriers to the spread of cancer. These membranes thicken medially to form the false vocal fold and the vocal ligament (the true vocal cord).
The supraglottic larynx contains pseudostratified, ciliated respiratory epithelium that covers the false vocal cords. The epiglottis and the vocal cords are lined by stratified, nonkeratinizing squamous epithelium. The subglottic mucosa is pseudostratified, ciliated respiratory epithelium. Minor salivary glands are also found in the supraglottic and subglottic. Tumor types that arise in the larynx are primarily squamous cell carcinoma but also include tumors of neuroendocrine origin, squamous papillomas, granular cell tumors, and tumors of salivary origin. Several histologic variants of squamous cell carcinoma exist and include verrucous, basaloid squamous cell, adenosquamous, and spindle cell carcinoma. Tumors of the laryngeal framework include synovial sarcoma, chondroma, and chondrosarcoma.
The normal functions of the larynx are airway patency, protection of the tracheobronchial tree during swallowing, and phonation. Patients with tumors of the supraglottic larynx may present with symptoms of chronic sore throat, dysphonia (“hot potato” voice), dysphagia, or a neck mass secondary to regional metastasis. Supraglottic tumors may cause vocal cord fixation by inferior extension in the paraglottic space or direct invasion of the cricoarytenoid joint. Anterior extension of tumors arising on the laryngeal surface of the epiglottis into the preepiglottic space produces a muffled quality to the voice. Referred otalgia or odynophagia is encountered with advanced supraglottic cancers. Bulky tumors of the supraglottic may result in airway compromise. In contrast to most supraglottic lesions, hoarseness is an early symptom in patients with tumors of the glottis.64 Airway obstruction from a glottic tumor is usually a late symptom and is the result of tumor bulk or impaired vocal cord mobility. Decreased vocal cord mobility may be caused by direct muscle invasion or involvement of the RLN. Fixation of the vocal cord indicates invasion into the vocalis muscle, paraglottic space, or cricoarytenoid joint. Superficial tumors that are bulky may appear to cause cord fixation through mass effect. Subglottic cancers are relatively uncommon and typically present with vocal cord paralysis (usually unilateral) and/or airway compromise.
The staging classification for squamous cell cancers of the larynx includes assessment of vocal cord mobility as well as local tumor extension. Accurate clinical staging of laryngeal tumors requires flexible fiber-optic endoscopy in the office and direct microlaryngoscopy under general anesthesia. Direct laryngoscopy, used to assess the extent of local spread, may be combined with esophagoscopy or bronchoscopy to adequately stage the primary tumor and to exclude the presence of a synchronous lesion. Key areas to note for tumor extension in supraglottic tumors are the vallecula, base of tongue, ventricle, arytenoid, and anterior commissure. For glottic cancers, it is important to determine extension to the false cords, anterior commissure, arytenoid, and subglottic.
Radiographic imaging by CT and/or MRI provides important staging information and is crucial for identifying cartilage erosion or invasion and extension into the preepiglottic or paraglottic spaces. High quality, thin-section images through the larynx should be obtained in patients with laryngeal tumors and used with clinical assessment to arrive at a final disease pretreatment staging. Lymph node metastasis may be defined more readily with the use of imaging studies.
Lymphatic drainage of the larynx is distinct for each subsite. Two major groups of laryngeal lymphatic pathways exist: those that drain areas superior to the ventricle, and those that drain areas inferior to it. Supraglottic drainage routes pierce the thyrohyoid membrane with the superior laryngeal artery, vein, and nerve, and drain mainly to the subdigastric and superior jugular nodes.64Those from the glottic and subglottic areas exit via the cricothyroid ligament and end in the prelaryngeal node (the delphian node), the paratracheal lymph nodes, and the deep cervical nodes along the inferior thyroid artery. Limited glottic cancers typically do not spread to regional lymphatics (1%–4%).However, there is a high incidence of lymphatic spread from supraglottic (30%–50%) and subglottic cancers (40%).
When considering treatment for laryngeal tumors, it is useful to categorize them as a continuum from early tumors (those with a small area of involvement resulting in minimal functional impairment) to advanced tumors (those with significant airway compromise and local extension). For example, severe dysplasia and carcinoma in situ often can be treated successfully with CO2 laser resection or conservative surgical approaches. In contrast, more advanced tumors may require partial laryngectomy (Fig. 18-33) or even total laryngectomy (Fig. 18-34).65 Further complicating the treatment paradigm is the role of radiotherapy, with or without chemotherapy, with the goal of laryngeal preservation.66
Example of the resection of a vertical partial laryngectomy for an early stage glottic carcinoma.
Total laryngectomy specimen featuring a locally invasive advanced stage glottic squamous carcinoma.
Prognostic factors for patients with cancer of the larynx are tumor size, nodal metastasis, perineural invasion, and extracapsular spread of disease in cervical lymph nodes. Patient comorbidities are important to consider when arriving at a treatment plan for patients with laryngeal cancer.
For severe dysplasia or carcinoma in situ of the vocal cord, complete removal of the involved mucosa with microlaryngoscopy is an effective treatment. Patients with limited involvement of the arytenoid or anterior commissure are the best candidates for a good posttreatment vocal quality result with this approach. Multiple procedures may be necessary to control the disease and to prevent progression to an invasive cancer. Close follow-up examinations and smoking cessation are mandatory adjuncts of therapy. For early stage cancers of the glottis and the supraglottis, radiation therapy is equally as effective as surgery in controlling disease.
Critical factors in determining the appropriate treatment modality are comorbid conditions (chronic obstructive pulmonary disease, cardiovascular, and renal disease) and tumor extension. Voice preservation and maintenance of quality of life are key issues and significantly impact therapeutic decisions. The use of radiation therapy for early stage disease of the glottis and supraglottis provides excellent disease control with reasonable, if not excellent, preservation of vocal quality. Partial laryngectomy for small glottic cancers provides excellent tumor control, but vocal quality can vary. For supraglottic cancers without arytenoid or vocal cord extension, standard supraglottic laryngectomy results in excellent disease control with good voice function. For advanced tumors with extension beyond the endolarynx or with cartilage destruction, total laryngectomy followed by postoperative radiation is considered the standard of care.67 In this setting, reconstruction by means of a pectoralis major flap (Fig. 18-35) or free flap reconstruction is required for lesions with pharyngeal extension.
Pectoralis flap reconstruction of a laryngectomy patient requires soft-tissue augmentation for pharynx closure.
Subglottic cancers, constituting only 1% of laryngeal tumors, are typically treated with total laryngectomy. Of note, 40% of patients with these tumors present with regional adenopathy and special attention must be directed to the treatment of paratracheal lymph nodes.68
Laryngeal Preservation Techniques
Superficial cancers confined to the true vocal cord can be treated with a variety of surgical options. These include endoscopic vocal cord stripping, microflap dissection, partial cordectomy, and CO2 laser resection. Although using a CO2 laser can provide excellent hemostasis and minimize damage to the adjacent uninvolved tissue, scarring associated with its use is considered more significant than with conventional “cold” techniques. Microflap dissection, using a subepithelial infusion of a saline-epinephrine solution into Reinke’s space, allows for assessment of depth of invasion and the ability to resect the lesion as a single unit. Use of an operative microscope aids the precision of such dissections. Open laryngofissure and cordectomy may be reserved for more invasive tumors.
For larger tumors of the glottis with impaired vocal cord mobility, a variety of partial resections exist that permit preservation of reasonable vocal quality. For lesions involving the anterior commissure with limited subglottic extension, an anterofrontal partial laryngectomy is indicated. For lateralized T2 or T3 glottic tumors without cartilage destruction, a vertical partial laryngectomy is feasible. In this circumstance, reconstruction is accomplished by means of a false vocal cord imbrication to simulate a true vocal cord on the side of the resection.
For T3 glottic lesions not involving the preepiglottic space or cricoarytenoid joint, a supracricoid laryngectomy with cricohyoidopexy or cricohyoidoepiglottopexy (CHEP) are options.65 The supracricoid laryngectomy technique uses the remaining arytenoids as the phonatory structures, which come into apposition with epiglottic remnant in the CHEP, or with the tongue base in the cricohyoidopexy. Oncologic advantages of this procedure include the complete removal of the paraglottic spaces and thyroid cartilage. The supracricoid laryngectomy with CHEP is associated with excellent disease control and a high rate of tracheostomy decannulation. Favorable deglutition rates and a breathy vocal quality are seen postoperatively with this procedure. For lesions with involvement of the cricoarytenoid joint and/or extension to the level of the cricoid, total laryngectomy is required.
The risk for aspiration is high following certain partial laryngectomies. Patient selection is vital to successful application of these techniques. Presurgical pulmonary assessment may be necessary. One simple measurement of functional reserve is to have the patient climb two flights of stairs. Those able to do so without stopping are more likely to be candidates for conservation surgical procedures.
The approach to the treatment for patients with advanced tumors of the larynx and hypopharynx has evolved over time. Chemoradiation has demonstrated the ability for comparable locoregional disease control and overall survival similar to open surgical approaches. The Radiation Therapy Oncology Group 91-11 trial demonstrated a higher laryngeal preservation rate among patients receiving concomitant chemotherapy and radiotherapy than in those patients receiving radiation alone or sequential chemotherapy followed by radiation therapy.69 A randomized laryngeal preservation trial of neoadjuvant induction chemotherapy followed by radiation therapy has yielded survival rates similar to those of laryngectomy, with the benefit of preservation of the larynx in 65% of patients.66 Surgical salvage is available in cases of treatment failure or recurrent disease.
Speech and Swallowing Rehabilitation
Involvement of a speech and swallowing therapist is critical in the preoperative counseling and postoperative rehabilitation of patients with laryngeal cancer. Speech rehabilitation options after total laryngectomy include esophageal speech, tracheoesophageal puncture, and use of an electrolarynx. Esophageal speech is produced by actively swallowing and releasing air from the esophagus which results in vibrations of the esophageal walls and pharynx. The sounds produced can be articulated into words. The ability to create esophageal speech depends on the motivation of patients and their ability to control the upper esophageal sphincter, allowing injection and expulsion of air in a controlled fashion. Unfortunately, less than 20% of postlaryngectomy patients develop fluent esophageal speech.
A tracheoesophageal puncture is a fistula created between the trachea and esophagus that permits placement of a one-way valve that allows air from the trachea to enter the upper esophagus. The valve prevents retrograde passage of food or saliva into the trachea. Patients that undergo placement of a tracheoesophageal puncture have a success rate of >80% in achieving functional speech.
For patients unable to develop esophageal speech, the electrolarynx creates vibratory sound waves when held against the neck or cheek. The vibrations create sound waves that the patient articulates into words. A disadvantage of the electrolarynx is the mechanical quality of the sound produced. This device is most useful in the postoperative period before training for esophageal speech.
Postoperative swallowing rehabilitation is another important task performed by the speech and swallowing team. Patient instruction in various swallowing techniques and evaluation for the appropriate diet consistency allow a patient to initiate oral intake of nutrition while minimizing the risk of aspirating. Flexible fiberoptic laryngoscopy can be performed transnasally and provides valuable information to assist in the assessment of dysphagia. The oral intake of various consistencies of liquids and solids can be observed with endoscopic assessment of laryngeal penetration. A similar assessment may be performed with a modified barium swallow allowing the analysis of the various phases of swallowing.
When patients present with cervical nodal metastases without clinical or radiologic evidence of an upper aerodigestive tract primary tumor, they are referred to as having an unknown primary. Given the difficulty in performing a detailed examination in the clinical setting of the base of tongue, the tonsillar fossa, and the nasopharynx, examination under anesthesia with directed tissue biopsy specimens has been advocated. Ipsilateral tonsillectomy, direct laryngoscopy with base of tongue and pyriform biopsy specimens, examination of the nasopharynx, and bimanual examination can allow for identification of a primary site in a portion of patients previously considered to have an unknown primary. In those individuals in whom a primary site cannot be ascertained, empiric treatment of the mucosal sources of the upper aerodigestive tract at risk (from nasopharynx to hypopharynx) and the cervical lymphatics with concomitant chemoradiation is advocated. For patients with advanced neck disease (N2a or greater) or with persistent lymphadenopathy after radiation, a postradiation neck dissection may be necessary. For patients in whom the primary lesion is identified, a more limited radiation treatment field may be used.
Nose and Paranasal Sinuses
The nose and paranasal sinuses are the sites of a great deal of infectious and inflammatory pathology. The diagnosis of tumors within this region is frequently made after a patient has been unsuccessfully treated for recurrent sinusitis and undergoes diagnostic imaging. Symptoms associated with sinonasal tumors are subtle and insidious. They include chronic nasal obstruction, facial pain, headache, epistaxis, and facial numbness. As such, tumors of the paranasal sinuses frequently present at an advanced stage. Orbital invasion can result in proptosis, diplopia, epiphora, and vision loss. Paresthesia within the distribution of CN V2 is suggestive of pterygopalatine fossa or skull base invasion and is generally a poor prognostic factor. Maxillary sinus tumors can present with loose dentition indicating erosion of the alveolar and/or palatal bones. Tumors found to arise posterior to Ohngren’s line are associated with a worse prognosis than are more anteriorly based lesions (Fig. 18-36).70
Example of the Ohngren’s line and the relationship to the maxilla.
A variety of benign tumors arise in the nasal cavity and paranasal sinuses and include inverted papillomas, hemangiomas, hemangiopericytomas, angiofibromas, minor salivary tumors, and benign fibrous histiocytomas. Fibro-osseous and osseous lesions, such as fibrous dysplasias, ossifying fibromas, osteomas, and myxomas, can also arise in this region. Additionally, herniation of intracranial contents into the nasal cavity can occur with the erosion of the anterior skull base with the resultant presentation of a sinonasal mass on clinical examination.
Malignant tumors of the sinuses are predominantly squamous cell carcinomas. Sinonasal undifferentiated carcinoma,71 adenocarcinoma, mucosal melanoma, lymphoma, olfactory neuroblastoma, rhabdomyosarcoma, and angiosarcoma are some of the other malignancies that have been described. Metastases from the kidney, breast, lung, and thyroid may also present as an intranasal mass. Regional metastasis is uncommon with tumors of the paranasal sinuses (14%–16%) and occurs in the parapharyngeal, retropharyngeal, and subdigastric nodes of the jugular chain.
The diagnosis of an intranasal mass is made with the assistance of a headlight and nasal speculum or nasal endoscopy. The site of origin, involved bony structures, and the presence of vascularity should be assessed. For paranasal sinus tumors, MRI and CT scanning often are complementary studies in determining orbital and intracranial extension.72 Benign processes frequently present as slow-growing expansile tumors with limited erosion of surrounding bone, compared to the lytic destruction typically associated with malignancies. Skull base foramen should be closely examined for enlargement that may be suggestive of perineural invasion. Examination for cavernous sinus extension, cribriform plate erosion, and dural enhancement is necessary to assess for resectability and the type of surgical approach that is possible. A meningocele or encephalocele will present as a unilateral pulsatile mass. Biopsy of a unilateral nasal mass should be deferred until imaging studies are obtained. An untimely biopsy specimen can result in a CSF leak. If hypervascularity is suspected, biopsy should be performed under controlled conditions in the operating room.
The standard treatment for malignant tumors of the paranasal sinuses is surgical resection with postoperative radiation therapy. Tumors arising along the medial wall of the maxillary sinus may be treated by means of a medial maxillectomy. The treatment of advanced tumors of the paranasal sinuses frequently involves a multispecialty approach. Members of this team include the head and neck surgeon, neurosurgeon, prosthodontist, ophthalmologist, and reconstructive surgeon. Each team member is necessary to facilitate the goal of safe and complete tumor removal. For vascular tumors, preoperative embolization performed within 24 hours of the planned surgical resection may reduce intraoperative hemorrhage.
Prognosis is dependent on tumor location and extension to the surrounding anatomy. Infrastructure maxillectomy, which includes removal of the hard palate and the lower maxillary sinus, is necessary for inferiorly based tumors of the maxillary sinus. For tumors in the upper portion of the maxillary sinus, complete maxillectomy (including removal of the orbital floor) is performed. If there is invasion of the orbital fat, exenteration of the orbital contents is required. Removal of the bony floor of the orbit and preservation of the globe are possible where there is absence of invasion through the orbital periosteum. However, reconstruction of the orbital floor to recreate a stable support for the orbital contents is essential. Removal of anterior cheek skin is indicated when there is tumor extension into the overlying subcutaneous fat and dermis.
For tumors involving the ethmoid sinuses, the integrity of the cribriform plate is assessed with preoperative imaging. Complete sphenoethmoidectomy or medial maxillectomy may suffice if the tumor is localized to the lateral nasal wall. Endoscopic resection with the assistance of image-guidance technology is gaining increasing acceptance for low-grade resectable lesions such as inverted papilloma.
If erosion of the cribriform has occurred, an anterior craniofacial resection is the standard operative approach. The head and neck surgeon and neurosurgeon work in concert to perform this procedure. The neurosurgeon performs a frontal craniotomy for exposure of the anterior cranial fossa floor, whereas the head and neck surgeon proceeds through a transfacial or endoscopic approach to resect the inferior bony attachments. Paranasal sinus malignancies that are deemed unresectable are those with bilateral optic nerve involvement, massive brain invasion, or carotid encasement.73 Postoperative rehabilitation after orbital exenteration is accomplished by soft-tissue reconstruction and placement of a maxillofacial prosthesis. Combined treatment with surgery and postoperative radiotherapy for squamous cell carcinoma of the sinuses results in survival superior to either radiation or surgery alone. Chemotherapy has a limited application and may be used for specific indications. Rhabdomyosarcoma is primarily treated with chemotherapy followed by radiation therapy. Surgery is reserved for persistent disease after chemoradiation. Sinonasal undifferentiated carcinoma is highly aggressive and typically is not adequately controlled with standard therapy. Chemotherapy in this setting may help to reduce the tumor bulk and allow for orbital preservation.
The nasopharynx extends in a plane superior to the hard palate from the choana, to the posterior nasal cavity, to the posterior pharyngeal wall. It includes the fossa of Rosenmüller, the Eustachian tube orifices (torus tubarius), and the site of the adenoid pad. Tumors arising in the nasopharynx are usually of squamous cell origin and range from lymphoepithelioma to well-differentiated carcinoma. However, the differential diagnosis for nasopharyngeal tumors is broad and also includes lymphoma, chordoma, chondroma, nasopharyngeal cyst (Tornwaldt’s cyst), angiofibroma, minor salivary gland tumor, paraganglioma, rhabdomyosarcoma, extramedullary plasmacytoma, and sarcoma.
Risk factors for nasopharyngeal carcinoma include area of habitation, ethnicity, and tobacco use. There is an increased incidence of nasopharyngeal cancer in southern China, Africa, Alaska, and in Greenland Eskimos. A strong correlation exists between nasopharyngeal cancer and the presence of EBV infection, such that EBV titers may be used as a means to follow a patient’s response to treatment.
Symptoms associated with nasopharyngeal tumors include nasal obstruction, posterior (level V) neck mass, epistaxis, headache, serous otitis media with hearing loss, and otalgia. Cranial nerve involvement is indicative of skull base extension and advanced disease. Lymphatic spread occurs to the posterior cervical, upper jugular, and retropharyngeal nodes. Bilateral regional metastatic spread is common. Distant metastasis is present in 5% of patients at presentation.
Examination of the nasopharynx is facilitated by the use of the flexible or rigid fiber-optic endoscope. Evaluation with imaging studies is important for staging and treatment planning. CT with contrast is used for determining bone destruction, while MRI is used to assess for intracranial and soft-tissue extension. Erosion or enlargement of neural foramina (on CT imaging) or enhancement of cranial nerves (on MRI) is indicative of perineural spread of disease and portends a worse prognosis. The status of the cavernous sinus and optic chiasm should also be assessed. The standard treatment for nasopharyngeal carcinoma is chemoradiation. Combination therapy produces superior survival rates for nasopharyngeal carcinoma in comparison to radiation alone.74 Intracavitary radiation boost with implants to the tumor may be included as an adjunct to external beam radiotherapy to improve local control of advanced tumors. Surgical treatment for nasopharyngeal carcinoma is rarely feasible, but may be considered in selected cases as salvage therapy for patients with localized recurrences.
For minor salivary gland and low-grade tumors of the nasopharynx, resection can be performed via a variety of approaches. Lateral rhinotomy or midface degloving approaches can provide good access for removal of tumors in the posterior nasal cavity extending into the nasopharynx. Endoscopic removal is also possible in selected cases. A variety of surgical approaches also exist for more posteriorly located tumors extending to the sphenoid and clivus. Transpalatal approaches used in combination with transmaxillary and transcervical routes can provide good surgical access in addition to providing adequate control of the carotid artery. The emergence of endoscopic techniques has provided a significant advancement in the surgical management of lesions in these two sites.
Tumors of the ear and temporal bone are uncommon and account for less than 1% of all head and neck malignancies. Primary sites include the external ear (pinna), EAC, middle ear, mastoid, or petrous portion of the temporal bone. The most common histology is squamous cell carcinoma. Minor salivary gland tumors, including adenoid cystic carcinoma and adenocarcinoma, may also present in this region. The pinna, because of its exposure to ultraviolet light, is a common site for basal cell and squamous cell carcinoma to arise. Direct extension of tumors from the parotid gland and periauricular skin may occur in this region. Metastases from distant sites occur primarily to the petrous bone and arise in the breast, kidney, lung, and prostate. In the pediatric population, tumors of the temporal bone are most commonly soft-tissue sarcomas. For advanced stage tumors with extensive temporal bone extension, the complex anatomy of the temporal bone makes removal of tumors with functional preservation challenging.
The diagnosis of tumors of the ear and temporal bone is frequently delayed because the initial presentation of these patients is mistaken for benign infectious disease. When patients fail to improve with conservative care and symptoms evolve to potentially include facial nerve paralysis or worsening hearing loss, the need for imaging and biopsy become obvious. Granulation tissue in the EAC or middle ear should be biopsied in patients with atypical presentations or histories consistent with chronic otologic disease.75The complexity of the temporal bone anatomy makes the use of imaging studies of paramount importance in the staging and treatment of tumors in this region.
Small skin cancers on the helix of the ear can be readily treated with simple excision and primary closure. Mohs’ microsurgery with frozen section margin control also can be used for cancer of the external ear. In lesions that are recurrent or invade the underlying perichondrium and cartilage, rapid spread through tissue planes can occur. Tumors may extend from the cartilaginous external canal to the bony canal and invade the parotid, temporomandibular joint, and skull base. For extensive, pinna-based lesions, procedures such as auriculectomy may be required. Postoperative radiation therapy may be required for advanced skin cancer with positive margins, perineural spread, or multiple involved lymph nodes.
Tumors involving the EAC and middle ear may present with persistent otorrhea, otalgia, EAC or periauricular mass, hearing loss, and facial nerve weakness or paralysis. The patient resembles the presentation of an external otitis unresponsive to standard medical therapy. Sleeve resections are reserved for small superficial tumors involving the cartilaginous external canal. Tumors involving the petrous apex or intracranial structures may present with headache and palsies of CN V and VI. The optimal treatment for tumors of the middle ear and bony external canal is en bloc resection followed by radiation therapy. Management of the regional lymphatics is determined by the site and stage of the tumor at presentation. Temporal bone resections are classified as lateral or subtotal (Fig. 18-37). The lateral temporal bone resection removes the bony and cartilaginous canal, tympanic membrane, and ossicles. The subtotal temporal bone resection includes the removal of the ear canal, middle ear, inner ear, and facial nerve. It is indicated for malignant tumors extending into the middle ear.
Examples of resection specimens for lateral temporal bone resection, subtotal temporal bone resection, and total temporal bone resection.
Postoperative radiation therapy in the treatment of malignancies of the temporal bone usually is indicated and improves local control over surgery alone. Five-year survival rates are approximately 50% for patients with tumors confined to the external canal and decrease with medial tumor extension. Prognosis is poor when tumor involves the petrous apex.76
The purpose of reconstruction after temporal bone resection is to provide vascularized tissue and bulk to the site of resection. Prevention of CSF leak by watertight dural closure and prevention of meningitis are important goals of repair. Additionally, the reconstruction enables protection of vascular structures and the surrounding bone to prepare the patient for postoperative radiation therapy. Commonly used reconstruction methods are regional pedicle myocutaneous flaps (e.g., pectoralis major) and free flaps (e.g., rectus abdominis, radial forearm, or latissimus dorsi). The loss of the pinna produces significant external deformity; however, a prosthetic ear may produce acceptable rehabilitation. When the facial nerve is sacrificed, rehabilitation is necessary and includes the use of interposition nerve grafts, hypoglossal to facial nerve anastomosis, and static or dynamic sling techniques. In patients with poor eye closure, taping of the eyelids and the liberal use of eye lubrication can prevent exposure keratitis. Additionally, tarsorrhaphy, lid-shortening procedures, and the use of gold weight implants can provide upper eyelid closure and protect the cornea.
The diagnostic evaluation of a neck mass requires a planned approach that does not compromise the effectiveness of future treatment options. A neck mass in a 50-year-old smoker/drinker with a synchronous oral ulcer is different from cystic neck mass in an 18-year-old that enlarges with an upper respiratory infection. As with all diagnoses, a complete history with full head and neck exam, including flexible laryngoscopy, are critical to complete evaluation. The differential diagnosis of a neck mass is dependent on its location and the patient’s age. In children, most neck masses are inflammatory or congenital. However, in the adult population, a neck mass >2 cm in diameter has a >80% probability of being malignant. Once the physician has developed a differential diagnosis, interventions to confirm or dispute diagnoses are initiated. Fine-needle aspiration (FNA), with or without the assistance of ultrasound or CT guidance, can provide valuable information for early treatment planning. The use of imaging (CT and/or MRI) is dictated by the patient’s clinical presentation. Imaging enables the physician to evaluate the anatomic relationships of the mass to the surrounding anatomy of the neck and sharpen the differential. A cystic lesion may represent benign pathology such as a branchial cleft cyst; however, it may also represent a regional metastasis of a tonsil/base of tongue squamous cell carcinoma or a papillary thyroid carcinoma. In this circumstance, evaluation of these potential primary sites can alter the planned operative intervention.
If a variety of diagnoses are still being entertained after FNA and imaging, an open biopsy may be necessary. For patients with the potential diagnosis of lymphoma, a biopsy sacrificing normal anatomical structures is not necessary. Ensuring appropriate processing of biopsied materials, sent in saline or in formalin, and sparing undue trauma to tissues can decrease the need for re-biopsy. Appropriate placement of the incision for an open biopsy should be considered if the need for neck dissection or composite resection is later required.
Patterns of Lymph Node Metastasis
The regional lymphatic drainage of the neck is divided into seven levels. These levels allow for a standardized format for radiologists, surgeons, pathologists, and radiation oncologists to communicate concerning specific sites within the neck (Fig. 18-38). The levels are defined as the following:
Levels of the neck denoting lymph node bearing regions.
Level I—the submental and submandibular nodes
Level Ia—the submental nodes; medial to the anterior belly of the digastric muscle bilaterally, symphysis of mandible superiorly, and hyoid inferiorly
Level Ib—the submandibular nodes and gland; posterior to the anterior belly of digastric, anterior to the posterior belly of digastric, and inferior to the body of the mandible
Level II—upper jugular chain nodes
Level IIa—jugulodigastric nodes; deep to sternocleidomastoid (SCM) muscle, anterior to the posterior border of the muscle, posterior to the posterior aspect of the posterior belly of digastric, superior to the level of the hyoid, inferior to spinal accessory nerve (CN XI)
Level IIb—submuscular recess; superior to spinal accessory nerve to the level of the skull base
Level III—middle jugular chain nodes; inferior to the hyoid, superior to the level of the cricoid, deep to SCM muscle from posterior border of the muscle to the strap muscles medially
Level IV—lower jugular chain nodes; inferior to the level of the cricoid, superior to the clavicle, deep to SCM muscle from posterior border of the muscle to the strap muscles medially
Level V—posterior triangle nodes
Level Va—lateral to the posterior aspect of the SCM muscle, inferior and medial to splenius capitis and trapezius, superior to the spinal accessory nerve
Level Vb—lateral to the posterior aspect of SCM muscle, medial to trapezius, inferior to the spinal accessory nerve, superior to the clavicle
Level VI—anterior compartment nodes; inferior to the hyoid, superior to suprasternal notch, medial to the lateral extent of the strap muscles bilaterally
Level VII—paratracheal nodes; inferior to the suprasternal notch in the upper mediastinum
Patterns of spread from primary tumor sites in the head and neck to cervical lymphatics are well described.77 The location and incidence of metastasis vary according to the primary site. Primary tumors within the oral cavity and lip metastasize to the nodes in levels I, II, and III. Skip metastases may occur with oral tongue cancers such that involvement of nodes in level III or IV may occur without involvement of higher echelon nodes (levels I & II). Tumors arising in the oropharynx, hypopharynx, and larynx most commonly spread to the lymph nodes of the lateral neck in levels II, III, and IV. Isolated level V lymphadenopathy is uncommon with oral cavity, pharyngeal, and laryngeal primaries. Malignancies of the nasopharynx and thyroid commonly spread to level V nodes in addition to the jugular chain nodes. Retropharyngeal lymph nodes are sites for metastasis from tumors of the nasopharynx, soft palate, and lateral and posterior walls of the oropharynx and hypopharynx. Tumors of the hypopharynx, cervical esophagus, and thyroid frequently involve the paratracheal nodal compartment, and may extend to the lymphatics in the upper mediastinum (level VII). The delphian node, a pretracheal lymph node, may become involved by advanced tumors of the glottis with subglottic spread.
The philosophy for the treatment of the cervical lymphatics in head and neck cancer has evolved significantly since the mid-1970s. The presence of cervical metastasis decreases the 5-year survival rate in patients with upper aerodigestive malignancies by approximately 50%. As such, adequate treatment of the N0 and N+ neck in these patients has always been viewed as a priority in an effort to increase disease-free survival rates. Traditionally, the gold standard for control of cervical metastasis has been the radical neck dissection (RND) first described by Crile. The classic RND removes levels I to V of the cervical lymphatics in addition to the SCM, internal jugular vein, and the spinal accessory nerve (CN XI). Any modification of the RND that preserves nonlymphatic structures (i.e., CN XI, SCM muscle, or internal jugular vein) is defined as a modified radical neck dissection (MRND). A neck dissection that preserves lymphatic compartments normally removed as part of a classic RND is termed a selective neck dissection (SND). Bocca and colleagues demonstrated that the MRND, or “functional neck dissection,” was equally effective in controlling regional metastasis as the RND, in addition to noting that the functional results in patients were superior.78 With outcome data supporting the use of SND and MRND, these procedures have become the preferred alternative for the treatment of cervical metastases when indicated.79,80
SND options have become increasingly popular given the benefits of improved shoulder function and cosmetic impact on neck contour compared to MRND. The principle behind preservation of certain nodal groups is that specific primary sites preferentially drain their lymphatics in a predictable pattern. Types of SND include the supraomohyoid neck dissection, the lateral neck dissection, and the posterolateral neck dissection.81 The supraomohyoid dissection, typically used with oral cavity malignancies, removes lymph nodes in levels I to III (Fig. 18-39). The lateral neck dissection, frequently used for laryngeal malignancies, removes those nodes in levels II through IV (Fig. 18-40). The posterolateral neck dissection, used with thyroid cancer, removes the lymphatics in levels II to V (Fig. 18-41). In the clinically negative neck (N0), if the risk for occult metastasis is >20%, elective treatment of the nodes at risk is generally advocated. This may be in the form of elective neck irradiation or elective neck dissection. An additional role of SND is as a staging tool to determine the need for postoperative radiation therapy. Regional control after selective dissection has been shown to be as effective for controlling regional disease as the MRND in the N0 patient. Awareness of the potential for “skip metastases,” in particular with lateral oral tongue lesions, may require extension of a standard SND to include additional levels for selected lesions.82 The treatment option selected for the primary site cancer is a significant factor in determining which therapeutic modality will be selected for the treatment of the regional lymphatics.
Shaded region indicates the region included in a supraomohyoid neck dissection.
Shaded region indicates the region included in a lateral neck dissection.
Shaded region indicates the region included in a posterolateral neck dissection.
For clinically N+ necks, frequently the surgical treatment of choice is the MRND or RND. SND options have been advocated by some authors for treatment of limited N1 disease, however, they do not have a role in the treatment of advanced N stage disease. When extracapsular spread, perineural invasion, vascular invasion, and the presence of multiple involved lymph nodes are noted, surgical management of the neck alone is not adequate.83 Adjuvant radiation therapy, and possibly chemoradiation, is indicated in these cases.
A planned postradiation neck dissection for patients undergoing radiation as a primary therapy is another indication for the use of neck dissection. In patients with existing advanced N stage disease (N2a or greater) or in patients with a partial response in the neck to therapy, neck dissection is performed 6 to 8 weeks after completion of radiation.
Regional metastases that encase the carotid artery or that demonstrate fixation of nodes to surrounding structures (e.g., prevertebral muscles) decrease 5-year survival rates significantly, to the range of 15% to 22%. The associated morbidity is high with procedures involving carotid resection (e.g., cerebrovascular accident and death) and must be weighed carefully when deciding if surgery is to be pursued. Surgically debulking metastatic disease does not improve survival and is not advocated. Recurrent neck metastasis after comprehensive neck dissection or radiation is associated with very poor survival.
Parapharyngeal Space Masses
The parapharyngeal space is a potential space, shaped like an inverted pyramid spanning the skull base to the hyoid. The boundaries of the space are separated by the styloid process and its associated fascial attachments into the “prestyloid” and “poststyloid” compartments.84 The contents of the prestyloid space are the parotid, fat, and lymph nodes. The poststyloid compartment is composed of CN’s IX to XII, the carotid space contents, cervical sympathetic chain, fat, and lymph nodes. Tumors in this space can produce displacement of the lateral pharyngeal wall medially into the oropharynx (Fig. 18-42), dysphagia, cranial nerve dysfunction, Horner’s syndrome, or vascular compression.
Parapharyngeal mass—prestyloid with prominent oropharyngeal presentation typical of a dumbbell tumor.
Of the masses found in the parapharyngeal space, 40% to 50% of the tumors are of salivary gland origin. Tumors of neurogenic origin such as paragangliomas (glomus vagale, carotid body tumor), schwannomas, and neurofibromas are responsible for 20% to 25% of parapharyngeal masses. Lymph node metastases and primary lymphoma represent 15% of lesions. With this in mind, when reviewing preoperative imaging, one can assume that tumors arising anterior to the styloid process are most likely of salivary gland origin, whereas those of the poststyloid compartment are vascular or neurogenic. This is helpful in that angiography is not as necessary for prestyloid lesions as it may be for vascular poststyloid tumors. If a paraganglioma is suspected, a 24-hour urinary catecholamine collection should be obtained to allow for optimal premedication for patients with functional tumors. Embolization may be considered for vascular tumors before surgery in an attempt to decrease intraoperative blood loss.
Surgical access to these tumors may require a transmandibular and/or lateral cervical approach. It is inadvisable to approach parapharyngeal space tumors transorally without having the necessary exposure and control of the associated vasculature that is afforded by these approaches. Some tumors of the parapharyngeal space (e.g., dumbbell tumors of deep parotid origin) are amenable to removal by a combined transparotid and transcervical approach while allowing for dissection and displacement of the facial nerve to assist removal of tumor.
A number of benign masses of the neck occur that require surgical management. Many of these masses are seen in the pediatric population. The differential diagnosis includes thyroglossal duct cyst, branchial cleft cyst, lymphangioma (cystic hygroma), hemangioma, and dermoid cyst.
Thyroglossal duct cysts represent the vestigial remainder of the tract of the descending thyroid gland from the foramen cecum, at the tongue base, into the lower anterior neck during fetal development. They present as a midline or paramedian cystic mass adjacent to the hyoid bone. After an upper respiratory infection, the cyst may enlarge or become infected. Surgical management of a thyroglossal duct cyst requires removal of the cyst, the tract, and the central portion of the hyoid bone (Sistrunk procedure), as well as a portion of the tongue base up to the foramen cecum. Before excision of a thyroglossal duct cyst, an imaging study such as ultrasound is performed to identify if normal thyroid tissue exists in the lower neck, and lab assay is performed to assess if the patient is euthyroid.
Congenital branchial cleft remnants are derived from the branchial cleft apparatus that persists after fetal development. There are several types, numbered according to their corresponding embryologic branchial cleft. First branchial cleft cysts and sinuses are associated intimately with the EAC and the parotid gland. Second and third branchial cleft cysts are found along the anterior border of the SCM muscle and can produce drainage via a sinus tract to the neck skin (Fig. 18-43). Secondary infections can occur, producing enlargement, cellulitis, and neck abscess that requires operative drainage. The removal of branchial cleft cysts and fistula requires removal of the fistula tract to the point of origin to decrease the risk of recurrence. The second branchial cleft remnant tract courses between the internal and external carotid arteries and proceeds into the tonsillar fossa. The third branchial cleft remnant courses posterior to the common carotid artery, ending in the pyriform sinus region. Cystic metastasis from squamous cell carcinoma of the tonsil or tongue base to a cervical lymph node can be confused for a branchial cleft cyst in an otherwise asymptomatic patient. Dermoid cysts tend to present as midline masses and represent trapped epithelium originating from the embryonic closure of the midline.
CT scan demonstrating a branchial cleft cyst with operative specimen.
Lymphatic malformations such as lymphangiomas and cystic hygromas can be difficult management problems. They typically present as mobile, fluid-filled masses. Because of their predisposition to track extensively into the surrounding soft tissues, complete removal of these lesions can be challenging. Recurrence and re-growth occur with incomplete removal. Cosmetic deformity and/or nerve injury can result when extensive surgical dissection is performed for large lesions. In newborns and infants, there is higher associated morbidity when cystic hygromas and lymphangiomas become massive, require tracheostomy, and involve the deep neck and mediastinum.
The fascial planes of the neck provide boundaries that are clinically applicable because they determine the pathway of spread of an infection. The deep cervical fascia is composed of three layers. These are the investing (superficial deep), pretracheal, and the prevertebral fascias. The superficial layer of the deep cervical fascia forms a cone around the neck and spans from skull base and mandible to the clavicle and manubrium. This layer surrounds the SCM muscle and covers the anterior and posterior triangles of the neck. The pretracheal fascia is found within the anterior compartment, deep to the strap muscles and surrounds the thyroid gland, trachea, and esophagus. This fascia blends laterally to the carotid sheath. Infections in this region may track along the trachea or esophagus into the mediastinum. The prevertebral fascia extends from the skull base to the thoracic vertebra and covers the prevertebral musculature and cervical spine. If an infection were to communicate anteriorly through the prevertebral fascia, it would enter the retropharyngeal space. Infectious extension into this space is complicated by the fact that this region, located posterior to the buccopharyngeal fascia, extends from the skull base to the mediastinum.
Tumors of the salivary gland are relatively uncommon and represent less than 2% of all head and neck neoplasms. The major salivary glands are the parotid, submandibular, and sublingual glands. Minor salivary glands are found throughout the submucosa of the upper aerodigestive tract with the highest density found within the palate. About 85% of salivary gland neoplasms arise within the parotid gland (Fig. 18-44). The majority of these neoplasms are benign, with the most common histology being pleomorphic adenoma (benign mixed tumor). In contrast, approximately 50% of tumors arising in the submandibular and sublingual glands are malignant. Tumors arising from minor salivary gland tissue carry an even higher risk for malignancy (75%).
Example of a tumor in the parotid with the pattern of the facial nerve and associated anatomy. m. = muscle; n. = nerve; v. = vein.
Salivary gland tumors are usually slow growing and well circumscribed. Patients with a mass and findings of rapid growth, pain, paresthesias, and facial nerve weakness are at increased risk of harboring a malignancy. The facial nerve, which separates the superficial and deep lobes of the parotid, may be directly involved by tumors in 10% to 15% of patients. Additional findings ominous for malignancy include skin invasion and fixation to the mastoid tip. Trismus suggests invasion of the masseter or pterygoid muscles.85
Submandibular and sublingual gland tumors present as a neck mass or floor of mouth swelling, respectively. Malignant tumors of the sublingual or submandibular gland may invade the lingual or hypoglossal nerves, causing paresthesias or paralysis.86 Bimanual examination is important for determining the size of the tumor and possible fixation to the mandible or involvement of the tongue.
Minor salivary gland tumors present as painless submucosal masses and are most frequently seen at the junction of the hard and soft palate. Minor salivary gland tumors arising in the prestyloid parapharyngeal space may produce medial displacement of the lateral oropharyngeal wall and tonsil.
The incidence of metastatic spread to cervical lymphatics is variable and depends on the histology, primary site, and stage of the tumor. Parotid gland malignancies can metastasize to the intra- and periglandular nodes. The next echelon of lymphatics for the parotid is the upper jugular nodal chain. Although the risk of lymphatic metastasis is low for most salivary gland malignancies, lesions that are considered high grade or that demonstrate perineural invasion have a higher propensity for regional spread. Tumors arising in patients of advanced age also tend to have more aggressive behavior. Initial nodal drainage for the submandibular gland is the level Ia and Ib lymph nodes and submental nodes followed by the upper and midjugular nodes. Extraglandular extension of tumor and lymph node metastases are adverse prognostic factors for submandibular gland tumors.
Diagnostic imaging is standard for the evaluation of salivary gland tumors. MRI is the most sensitive study to determine soft-tissue extension and involvement of adjacent structures. Unfortunately, imaging studies lack the specificity for differentiating benign and malignant neoplasms. Diagnosis of salivary gland tumors is frequently aided by the use of FNA. In the hands of an experienced cytologist familiar with salivary gland pathology, FNA can provide an accurate preoperative diagnosis in 70% to 80% of cases. This can help the operative surgeon with treatment planning and patient counseling, but should be viewed in the context that a more extensive procedure may be ultimately required. The final histopathologic diagnosis is confirmed by surgical excision.
Benign and malignant tumors of the salivary glands are divided into epithelial, nonepithelial, and metastatic neoplasms. Benign epithelial tumors include pleomorphic adenoma (80%), monomorphic adenoma, Warthin’s tumor, oncocytoma, or sebaceous neoplasm. Nonepithelial benign lesions include hemangioma, neural sheath tumor, and lipoma. Treatment of benign neoplasms is surgical excision of the affected gland or, in the case of the parotid, excision of the superficial lobe with facial nerve dissection and preservation. The minimal surgical procedure for neoplasms of the parotid is superficial parotidectomy with preservation of the facial nerve. Enucleation of the tumor mass is not recommended because of the risk of incomplete excision and tumor spillage. Tumor spillage of a pleomorphic adenoma during removal can lead to problematic recurrences.
Malignant epithelial tumors range in aggressiveness from low to high grade. Their behavior depends on tumor histology, degree of invasiveness, and the presence of regional metastasis. The most common malignant epithelial neoplasm of the salivary glands is mucoepidermoid carcinoma. The low-grade mucoepidermoid carcinoma is composed of largely mucin-secreting cells, whereas in high-grade tumors, the epidermoid cells predominate. High-grade mucoepidermoid carcinomas resemble nonkeratinizing squamous cell carcinoma in their histologic features and clinical behavior. Adenoid cystic carcinoma, which has a propensity for neural invasion, is the second most common malignancy in adults. Skip lesions along nerves are common and can lead to treatment failures because of the difficulty in treating the full extent of invasion. Adenoid cystic carcinomas have a high incidence of distant metastasis, but display indolent growth. It is not uncommon for patients to experience lengthy survival despite the presence of disseminated disease. The most common malignancies in the pediatric population are mucoepidermoid carcinoma and acinic cell carcinoma. For minor salivary glands, the most common malignancies are adenoid cystic carcinoma, mucoepidermoid carcinoma, and low-grade polymorphous adenocarcinoma. Carcinoma ex pleomorphic adenoma is an aggressive malignancy that arises from a preexisting benign mixed tumor.
The primary treatment of salivary malignancies is surgical excision. In this setting, basic surgical principles include the en bloc removal of the involved gland with preservation of all nerves unless directly invaded by tumor. For parotid tumors that arise in the lateral lobe, superficial parotidectomy with preservation of CN VII is indicated. If the tumor extends into the deep lobe of the parotid, a total parotidectomy with nerve preservation is performed. Although malignant tumors may about the facial nerve, if a plane of dissection can be developed without leaving gross tumor, it is preferable to preserve the nerve. If the nerve is encased by tumor (or is noted to be nonfunctional preoperatively) and preservation would result leaving gross residual disease, nerve sacrifice should be considered.
The removal of submandibular malignancies includes en bloc resection of the gland and submental and submandibular lymph nodes. Radical resection is indicated with tumors that invade the mandible, tongue, or floor of mouth. Therapeutic removal of the regional lymphatics is indicated for clinical adenopathy or when the risk of occult regional metastasis exceeds 20%. High-grade mucoepidermoid carcinomas, for example, have a high risk of regional disease and require elective treatment of the regional lymphatics. When gross nerve invasion is found (lingual or hypoglossal), sacrifice of the nerve is indicated with retrograde frozen section biopsy specimens to determine the extent of involvement. If the nerve is invaded at the level of the skull base foramina, a surgical clip may be left in place to mark the area for inclusion in postoperative radiation fields. The presence of skip metastases in the nerve with adenoid cystic carcinoma makes recurrence common with this pathology.
Postoperative radiation treatment plays an important role in the treatment of salivary malignancies. The presence of extraglandular disease, perineural invasion, direct invasion of regional structures, regional metastasis, and high-grade histology are all indications for radiation treatment.