[A painful subungual nodule: subungual exostosis].

Subungual exostosis is an acquired, benign, often painful, and nearly always solitary bone tumor usually occurring in the dorsal medial aspect of the phalanges. An eighteen-year-old male patient presented with a progressively enlarging mass and pain that developed over two years in the distal medial aspect of the right first toe. Conventional radiographs, computed tomography, and histopathologic findings showed subungual exostosis. Complete removal of the tumor was performed including its base in the cortex of the phalanx. No recurrence was observed during a follow-up of 11 months. It was emphasized that clinical presentation of subungual exostosis may resemble other benign or malignant bone tumors.