Traumatic neuroma of the lower lip with intraepithelial nerve fibers.

A 42-year-old man had noticed a small tender papule on his lower lip, and the papule clinically became unnoticeable after cryosurgery. He visited our clinic because the lesion recurred up to the original size after 9 months. On examination, a linear scar and a papule, 4 mm in diameter, were observed on the mucosal lower lip. The papule was resected and histopathologically showed proliferation of nerve fibers in irregular and tortuous fascicles, thus establishing the diagnosis of traumatic neuroma. Immunohistochemical staining by antineuron-specific enolase (NSE) antibody showed proliferation of axons in the upper lamina propria and even in the mucosal epithelium overlying the tumor. Traumatic neuroma of the lower lip is very rare, and a literature search showed only one reported case. Intraepithelial proliferation of axons may be one of the characteristics of mucosal traumatic neuroma.