The dermal component in melanosis naeviformis Becker.

Histological investigations were performed in 11 subjects suffering from melanosis naeviformis Becker. Apart from the well-known epidermal alterations such as basal hyperpigmentation, slight acanthosis and growth of coarse hair, dermal changes were found in each case. The dermis was considerably thickened and contained numerous small and/or large bundles of smooth muscle without relation to cutaneous adnexa. Thus, melanosis naeviformis Becker can be considered an organoid nevus with epidermal, melanocytic and dermal components.