Chondroblastoma: a clinical and radiological study of 104 cases

The clinical and radiographic findings in 104 patients with chondroblastoma are presented. Pain was an almost constant presenting complaint, often accompanied in the case of para-articular lesions by impaired function of an adjacent joint. The majority (80%) were in long bones with a mean age of presentation of 16 years. The characteristic radiological image of these lesions was an eccentric radiolucency, having a sharply defined sclerotic margin and containing areas of calcification in approximately a third of cases. They were always related to a growth plate. Nearly half were confined to the affected epiphysis or apophysis itself, but most of the remainder had traversed the growth plate to involve also the adjacent metaphysis. The bones around the knee and the proximal ends of the humerus and femur were the sites of predilection. A minority (20%) affected flat bones and short tubular bones of the hand and foot, with a peculiar affinity for the calcaneus and talus. The mean age of presentation of these was 28 years. The radiological pattern was similar, except for a greater tendency to expand the affected bone. Complications included the formation of a secondary aneurysmal bone cyst in 16 cases (10 of them in long bones), one malignant chondroblastoma, and one fibrosarcoma developing after radiation of the original chondroblastoma.