Diagnosis and treatment of basal cell and squamous cell carcinomas.

Rates of squamous cell and basal cell carcinomas have been increasing, possibly as a result of increased exposure to ultraviolet radiation. Primary care physicians can expect to diagnose six to seven cases of basal cell carcinoma and one to two cases of squamous cell carcinoma each year. Basal cell carcinomas may be plaque-like or nodular with a waxy, translucent appearance, often with ulceration and telangiectasia. They rarely metastasize and are treated with excision, cryotherapy, electrodesiccation and cautery, imiquimod, 5-fluorouracil, or photodynamic therapy (the latter is not approved for this purpose by the U.S. Food and Drug Administration), although surgery results in the fewest recurrences. Actinic keratoses are scaly keratotic patches that often are more easily felt than seen. They are amenable to any of the destructive techniques described above, with the exception of photodynamic therapy. Squamous cell carcinomas arise from keratotic patches and become more nodular and erythematous with growth, sometimes including keratin plugs, horns, or ulceration. Because they may metastasize, they often are treated with excisional biopsy.