basal cell carcinoma [Gk, basis + L, cella, storeroom; Gk, karkinos, crab, oma, tumor] , a malignant epithelial cell tumor that begins as a pearly-appearing papule and enlarges peripherally, developing a central crater that erodes, crusts, and bleeds. Metastasis is rare, but local invasion destroys underlying and adjacent tissue. It occurs most frequently in sun-exposed areas of the body, such as the face, ears, neck, scalp, shoulders, and back. The primary known cause of the cancer is excessive exposure to the sun or to radiation. Treatment is eradication of the lesion, often by electrodesiccation, laser, or cryotherapy. Lesions may also be treated with topical or injection chemotherapy or radiation. Also called basal cell epithelioma, basaloma, basiloma, carcinoma basocellulare, hair matrix carcinoma. See also rodent ulcer.
