Chondroblastoma of a metacarpal bone mimicking an aneurysmal bone cyst: a case report and a review of the literature.

Chondroblastoma of the metacarpal bone has been extremely rare and only seven cases have been reported in the English literature. Here we reported the eighth case of a chondroblastoma that developed on the first metacarpal bone of the right hand of a 21-year-old man. Radiographs showed an expansile osteolytic lesion with a multilocular appearance. In MR images, the lesion showed low intensity in T1 and high intensity in T2-weighted images with multiple fluid-fluid levels, which are findings resembling those of an aneurysmal bone cyst. From the pathological findings, however, it was recognized as a chondroblastoma with aneurysmal bone cyst-like change. Good clinical results was obtained by the subtotal resection of the metacarpal bone with a columnar-shaped iliac bone graft.