The subungual exostosis is a benign bone tumor on the distal phalanx of a digit, beneath or adjacent to the nail, often bringing in discussion many differential diagnosis. We present a 14-year-old boy with a cutaneous nodular lesion, painful to the easy touch on the latero-internal half of the nail of right big toe with extension in the cutaneous part of this. He suffered many treatments, especially cauterization, but with recurrence. In the present, the radiological findings of the affected finger and the histopathological ones from the fragment excised confirmed the diagnosis of subungual exostosis. The local excision of the entire region with the removal of the cartilaginous cap has been followed by a silent period without recurrences of almost two years when he as revised.