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Basal cell carcinoma (BCC) is the most common cancer in humans. Risk factors for basal cell cancer include older age, ultraviolet exposure, fair skin, exposure to ionizing radiation or arsenic, and rare germline genetic mutations in PTCH1, SUFU (Gorlin Syndrome/Basal Cell Nevus syndrome), and, very rarely, other genes. BCC can be further subtyped by histopathologic criteria into superficial, nodular, micronodular, morpheaform, fibroepithelioma of pinkus, and basosquamous. Standard of care is predominantly surgical excision but topical treatments may be appropriate for low-risk BCCs based on the histologic subtype, size, and location on the body (not H-zone of face). The vast majority of BCCs are low-risk. High-risk features of BCC include large size (>20 mm diameter on trunk or extremities, >10 mm on cheeks, forehead, or neck, >6 mm H zone), morpheaform or infiltrative subtypes, poorly defined tumor borders, perineural invasion, recurrence, previous radiation treatment, or an immunosuppressed host. Very rarely, BCCs can become locally advanced (inoperable) or metastatic requiring systemic chemotherapy. Comprehensive consensus guidelines have been published previously (level of evidence IV).1,2 See Tables 101-1 and 101-2.
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