Cutaneous malignancies are the most common cancers in humans. Skin cancers have the potential to cause local destruction, distant metastasis, and death. Various treatment modalities are utilized to treat cutaneous malignancies depending on their histologic type, anatomic location, size, and host characteristics. Treatment may include topical chemotherapy, cryosurgery, electrodesiccation and curettage, standard surgical excision, staged excision, radiation therapy, or Mohs micrographic surgery. The management of cutaneous malignancies of the head and neck presents a unique set of challenges to the physicians who treat them. One must prioritize complete tumor extirpation with free margins while also maintaining function and cosmesis. This chapter reviews the types of cutaneous malignancies likely to be encountered in the practice of otolaryngology including nonmelanoma skin cancer, cutaneous melanoma, and other less common cutaneous malignancies.
NONMELANOMA SKIN CANCER
Nonmelanoma skin cancer (NMSC), sometimes termed keratinocyte carcinoma, is a term that encompasses basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC). NMSC has an annual incidence in the United States of approximately 5.4 million based on a 2012 study that estimated this incidence from the total number of procedures performed for these cancers. Furthermore, in the United States, cutaneous malignancies account for a higher cancer burden than all other cancers combined. Approximately 95% of these are NMSCs. In individuals with fair skin, approximately 75% to 80% of NMSCs are BCCs and 25% are SCCs. Numerous treatment modalities are available for the local treatment of NMSC. These include excisional surgery, electrodesiccation and curettage, cryotherapy, topical immunotherapy and chemotherapy, photodynamic therapy, radiation therapy, and Mohs micrographic surgery (MMS). For advanced and metastatic disease, systemic therapies may be utilized.
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AW. Lifetime risk for development of skin cancer in the U.S. population: current estimate is now 1 in 5. J Am Acad Dermatol.
BCC is a malignant neoplasm that arises from nonkeratinizing cells in the basal layer of the epidermis. BCC is the most common skin cancer in humans with a male-to-female ratio 0.92:1. Furthermore, BCC occurs at a higher ratio to SCC in younger patients than older patients. In patients under 30 years old, BCC occurs with a 3.5:1 ratio to SCC. After age 60 years, BCC occurs in a 1.8:1 ratio to SCC. The primary risk factor for the development of BCC is exposure to ultraviolet (UV) light, particularly in the UVB spectrum. Exposure to UVB can lead to mutations in the Hedgehog signaling pathway. This pathway includes the Patched gene, which is a tumor suppressor for the Smoothened (SMO) gene. Both loss of function mutations in Patched and activating mutations in SMO have ...