Subungual Exostosis

**Semantic type:** Neoplastic Process

**Definition:** A benign tumor that affects the distal phalanx, most often the great toe. Grossly it consists of a cartilage cap and a bony stalk. Microscopically it is characterized by an osteochondromatous proliferation with a gradual transition of a peripheral spindle-cell proliferation to hyaline cartilage to trabecular bone. Pain and swelling are present. Simple resection is usually curative.

**Synonyms:** - Dupuytren Exostosis