Cutaneous Horn Arising From a Seborrheic Keratosis

A 72-year-old woman complained about the recent appearance of a slightly painful lesion on the upper abdominal skin. She otherwise felt well and had no previous skin complaints.

Key point: Physical examination revealed a firm and tender exophytic papule on the left upper abdominal quadrant that was 4 mm long. The lesion had a red, fleshy base surmounted by a column of firm, keratotic material. The morphology is typical for a cutaneous horn.

Treatment: The lesion was removed by deep shave, and the resulting specimen was sent, in its entirety, for histopathologic evaluation. The lesion base proved to be a seborrheic keratosis.

Note: Cutaneous horns can arise on top of seborrheic keratoses, actinic keratoses, warts, basal and squamous cell carcinomas. Therefore, the lesion (and especially the base) must be submitted for pathologic diagnosis. Simple, conservative removal is appropriate for some diagnoses, while others (BCC, SCCA) may require re-excision or other destructive intervention.