Seborrheic Keratoses

A 70-year-old man was concerned about these dark lesions that covered his back and legs.

Sunita Puri, MD, of Decatur, Ala, diagnosed seborrheic keratoses. Also called seborrheic wart and verruca seborrheica, these benign growths can present as a single tumor or as crops of lesions. They often appear on the face, trunk, and legs—where sebaceous glands are most common—and generally do not appear on palms, soles, and mucous membranes.

Initially, seborrheic keratoses are flat, sharply demarcated, brown maculae. Over time, the lesions become polypoid with an uneven surface and may be warty, dark brown or black, and greasy (A). They are identified by their “stuck-on” appearance. On the trunk, they may develop in the pattern of a “Christmas tree” (B), as in this case. Because clothes and jewelry can catch on the lesions, they are considered cosmetically undesirable and annoying.

The age of onset is typically after the fifth decade. Men and women with a familial tendency are equally affected. Rarely, a sudden appearance of multiple lesions may be associated with underlying malignancy.¹ When there is diagnostic doubt, or when a skin cancer is suspected, a biopsy is indicated. These lesions can be removed with cryosurgery, curettage, or laser therapy. This patient