04 Malignant Skin Lesions

Incidence and epidemiology basal cell carcinoma bcc

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Unformatted text preview: sion can be highly challenging. Incidence and Epidemiology Basal cell carcinoma (BCC) is the most common malignancy in white persons7 and the most prevalent type of skin cancer overall. The incidence varies widely across the globe (e.g., 146/100,000 in the United States, compared with 726/100,000 in Australia).8 The lifetime risk of BCC for a white person in the United States is approximately 30%.1 Although BCCs have a very low metastatic potential, they impose heavy economic and social burdens on patients and society. The vast majority of BCCs are found on the head and neck. There is no known precursor lesion. The risk of development of BCC seems to be most closely related to exposure to ultraviolet radiation. Whereas substantial sun exposure during childhood and adolescence increases the risk of BCC, no studies have demonstrated any significant correlation between the development of BCC and cumulative exposure to ultraviolet light in adulthood.9 Several heritable conditions are associated with an increased risk of BCC, including albinism, xeroderma pigmentosum, and Gorlin syndrome. Patients with Gorlin syndrome typically have multiple BCCs, as well as anomalies of the spine and the ribs, jaw cysts, pitting of the palms and the soles, and calcification of the falx cerebri. This syndrome is inherited in an autosomal-dominant fashion.10 Histologic Subtypes Several subtypes of BCC have been identified. Typical patterns seen in more mature lesions include nodular or cystic BCC, superficial BCC, morpheaform BCC, and pigmented BCC. Nodular BCC, also known as rodent ulcer, is the classic type. Nodular BCCs typically present as solitary lesions, often on the face, and are usually shiny and red with central telangectasias [see Figure 1a], an indurated edge, and an ulcerated center. If the contents of the lesion are soft and can be expressed, the condition is referred to as cystic BCC. Superficial BCC is typically found on the trunk and appears as a slowgrowing erythematous patch that is often mistaken for eczema or psoriasis.10 Morpheaform BCC [see Figure 1b] accounts for only a minority of these lesions, but it exhibits clinical features that are especially noteworthy for surgeons. In particular, morpheaform BCCs a Treatment Surgical excision remains the mainstay of treatment for primary BCCs.Typically, a surgical margin of 4 mm is recommended when possible.11 With small defects, primary closure is generally feasible; with larger defects, rotation flaps or skin grafting may be necessary. Lymphatic spread identified in the primary tumor, though present only in extraordinarily rare cases, may be an indication for lymphatic mapping.12 Other surgical techniques used to treat BCC include cryosurgery, curettage and cauterization, and Mohs’ micrographic surgery. Cryosurgery and curettage are generally contraindicated for large or morpheaform BCCs or tumors in high-risk areas (e.g., the central face), because surgical margins cannot be assessed. Mohs’ micrographic surgery involves excision of serial sections with intraoperative histologic exam...
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This note was uploaded on 03/21/2011 for the course ONC 01 taught by Professor Dzodic during the Spring '11 term at Multimedia University, Cyberjaya.

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