[Pigmented neurofibroma].

In a 24-year-old male melanin synthesis was demonstrated in a neurofibroma by light and electron microscopy. Although it is unclear whether the tumor cells are pigment-synthesizing Schwann cells or whether they originate from a coexisting melanocytic tumor, this tumor again demonstrates the close relationship between peripheral nerve sheath tumors and melanocytic malformations, as for example cellular blue nevi.