Diagnosis and management of basal cell carcinoma

Basal cell carcinomas (BCCs) are common skin cancers that tend to appear on sun-exposed skin. Pathobiologically, activation of the Hedgehog signaling pathway characterizes the majority of cases. In general, BCCs are slow-growing and rarely metastasize. Nevertheless, they are locally invasive and can be destructive. While typical cases are diagnosed based on clinical findings, the clinicopathological manifestations are varied. Consequently, skin biopsy is essential to confirm the diagnosis and evaluate the risk of recurrence. In the treatment of primary lesions, the initial goal is to complete tumor removal, whether by conventional surgical excision, Mohs micrographic surgery, cryosurgery, electrodesiccation and curettage, topical application of imiquimod or fluorouracil, photodynamic therapy, or radiation therapy. Of these treatments, surgical excision and Mohs surgery are the most commonly used because of their association with a low recurrence rate and the ability to confirm residual tumor pathologically. However, other treatment options may be preferred according to patient condition, tumor location, and risk of recurrence. In the treatment of metastatic or locally advanced lesions, smoothened inhibitors, which inhibit Hedgehog signaling pathway activation, were recently approved and impressive tumor shrinkage effects have been described. Although the exact prognosis of metastatic BCC has not been analyzed, it is probably poor due to the rarity of such condition. However, emerging molecular targeting agents hold therapeutic promise.