Tenosynovial osteochondromatosis of the extensor tendon of a digit: case report and review of the literature.

Extra-articular tenosynovial osteochondromatosis in the hand rarely occurs. A case of tenosynovial osteochondromatosis of the extensor tendon of the digit is reported. None of the cases reported in the literature have involved the extensor aspect of the digits. A possible explanation for the paucity of this lesion in relation to the extensor tendons of the digits is the absence of a tendon sheath on the dorsum of the digits.