Clinical, Radiologic, and Histopathologic Features that Distinguish a Pigmented Plexiform Neurofibroma from a Congenital Melanocytic Nevus.

A 13-year-old Hispanic boy with no significant medical etymology presented with a chief complaint of widespread brown macules and patches. He had a large and evenly pigmented brown patch, with a centrally located 2.2 cm × 1.2 cm soft and darkly pigmented plaque, which became more apparent with tension applied to the surrounding skin (Figure 1). The patient's mother stated that the plaque was present since birth and had increased in size over time. The clinical differential diagnoses included a congenital melanocytic nevus (CMN), a large café au lait macule (CALM), and a Becker's nevus with a congenital smooth muscle hamartoma.