Chondrosarcoma of the hand arising from a pre-existent benign solitary enchondroma.

Chondrosarcomas of the hand are relatively rare. Chondrosarcomas may arise by malignant transformation of a pre-existing enchondroma, but this causal relationship has been difficult to establish in solitary enchondroma. This is a case report of a chondrosarcoma of the proximal phalanx of the right index finger in a 66-year-old woman demonstrating histologic evidence of malignant transformation of a pre-existent benign solitaary enchondroma. Careful analysis of the preoperative X-ray for punctate endosteal calcification or cortical expansion and ample histologic sampling of the endosteal component of chondrosarcomas arising from within bone may demonstrate a greater incidence of preexistent enchondroma.