Linear arrangement of multiple congenital melanocytic nevi.

A 28-year-old man had numerous slightly papillomatous melanocytic nevi that were arranged in a linear pattern on his right arm. Their distribution was reminiscent of the lines of Blaschko. The nevi had been present since birth and were in part covered with terminal hair. Histopathologic examination showed typical features of congenital melanocytic compound nevi. In addition, the blue-eyed patient showed an iris bicolor in the form of a sectorial brown pigmentation of his right iris. This unusual case may provide a clue to the genetic basis of pigmented nevi.