Segmental Becker's nevi with mucosal involvement.

Becker's nevus otherwise known as Becker's pigmented hairy nevus, is a common melanotic epidermal hypermelanosis. It usually presents as a large unilateral patch of hyperpigmentation and hypertrichosis on the shoulder, chest, or back of an adult man. It can be bilateral or multiple and affect areas other than the usual sites. We report a 16-year-old boy with two Becker's nevi on the left side of the face in a segmental distribution with extension onto the oral mucosa. This case is being reported for its rare presentation.