Becker's melanosis: an ultrastructural study.

Becker's melanosis is an uncommon condition characterized by hypertrichosis, hyperpigmentation of the epidermis, dermal melanophages and absence of nevus cells. Ultrastructural examination of such a melanotic lesion from a young white man revealed giant melanosomes. In addition, normal-sized melanosomes were found singly in the keratinocytes of the involved skin. Dermal venules were surrounded by multiple layers of basement membrane.