Distal phalangeal bone cysts: differentiation of enchondromata and epidermal cysts.

Enchondromas are common in the hand but less frequent in the distal phalanges. Epidermal cysts are rare in the hand but when they occur can be difficult to differentiate from enchondromas both clinically and radiologically. Our review of seven distal phalangeal bone lesions treated over 7 years included four enchondromas and three epidermal cysts. The patients with epidermal cysts all had a history of previous penetrating trauma 5-8 years earlier. One patient with an enchondroma had a history of a penetrating injury. Patients presenting with distal phalangeal lesions and a history of previous penetrating injury appear more likely to have an epidermal cyst than an enchondroma. This is important as there may be a higher recurrence rate following curettage and bone grafting.