Subungual mass, not always soft tissue

Subungual exostosis is a benign bone tumor, very unusual in childhood, which is usually located in the distal phalanx of the first toe. It presents as a painful tumoration that affects the overlying nail and the periungual soft tissues. The differential diagnosis includes dermatological lesions such as common warts or pyogenic granuloma, and bone tumors such as osteochondroma. The final diagnosis is based on the radiological and histopathological findings. The treatment is surgical excision and the outcome is usually favourable.