Genital porokeratosis.

A 22-year-old man presented with a two-year history of warts on the penis, scrotum, and thighs. Physical examination showed multiple annular plaques with thin, threadlike borders on the penis and scrotum. The biopsy specimen showed a cornoid lamella with underlying dyskeratotic cells that was consistent with porokeratosis. Genital porokeratosis is a rare condition that may be misdiagnosed as a sexually transmitted disease.