Subungual Exostosis of the Hand: A Case Report in a 5-Year-Old Boy and Literature Review.

Subungual exostosis is a relatively uncommon benign tumor that occurs at the distal end of the distal phalanx of the toes and rarely the hands. We present in this article a review of the currently published English literature and provide a case report of a 5 year old male with subungual exostosis of the thumb. A 5 year old male presented with a slow growing mass of the distal dorsal aspect of the left thumb. Radiographs showed dorsal calcifications on the thumb. Surgical removal of the mass and histopathological analysis was performed supporting a diagnosis of subungual exostosis. Post-operatively, the patient had complete excision of the mass, normal nail morphology, no reoccurrence, and no post-surgical complications. Subungual exostosis remains a rare entity especially in the upper extremity. Its cause is not fully understood, nor is there an agreed upon method of treatment. However, with careful dissection during surgical removal good outcomes can be obtained. To our knowledge, this is the largest literature review on subungual exostosis and our case report is an uncommon presentation in the youngest reported male patient. It is our hope that this literature review and case report lend to increased awareness of subungual exostosis and how to diagnose and treat this lesion.