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ESSENTIALS OF DIAGNOSIS
The differential diagnosis of a neck mass is primarily guided by anatomic location, physical characteristics of the mass, and patient age.
Due to ease of acquisition, relative low cost, and 3-dimensional detail, computed tomography (CT) scan is the initial imaging modality of choice in the majority of adult neck masses.
Fine-needle aspiration (FNA) biopsy is the preferred approach to obtain diagnostic tissue in most neck masses.
Core biopsy should be considered when FNA is insufficient and excisional or incisional biopsy performed only in carefully evaluated and selected cases.
Human papillomavirus (HPV)-associated squamous cell carcinoma (SCC) must be considered and ruled out in any adult cystic neck mass.
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Knowledge of the anatomy of the neck is essential for both the diagnosis and the treatment of disease processes in the region. Contained within the neck are several triangles, defined anatomically (Figure 27–1). Familiarity with these specific areas assists in generating a differential diagnosis of neck masses by the exact anatomic location.
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The sternocleidomastoid muscle divides the neck into 2 major compartments, anterior and lateral.
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The following anatomic points define the anterior compartment of the neck: (1) the inferior border of the mandible superiorly, (2) the anterior border of the sternocleidomastoid muscle laterally, (3) the clavicle inferiorly, and (4) the vertical midline from mental symphysis to suprasternal notch medially. The structures that make up the anterior neck include the larynx, trachea, esophagus, thyroid and parathyroid glands, carotid sheath, and suprahyoid and infrahyoid strap muscles.
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Triangular regions also define the anterior neck anatomically.
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The submandibular triangle is a region contained in the anterior neck bordered by the inferior margin of the mandible and the digastric, stylohyoid, and mylohyoid muscles. This region contains the submandibular gland and the marginal mandibular branch of the facial nerve. The submental triangle defines a region bordered by the hyoid bone, the paired anterior bellies of the digastric muscles, and the mylohyoid muscle. The upper belly of the omohyoid muscle in the anterior neck further divides the anterior neck into an upper carotid triangle and a lower muscular triangle.
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The lateral neck, also referred to as the posterior triangle, is defined by the posterior aspects of the sternocleidomastoid muscle medially, the trapezius muscle laterally, and the middle third of the clavicle inferiorly. The lateral neck contains lymph node–bearing tissue, the spinal accessory nerve, and the cervical plexus. The inferior belly of the omohyoid muscle further defines a lower subclavian triangle in the lateral neck that contains the brachial plexus and subclavian vessels.
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The differential diagnosis in a patient presenting ...