Chondroblastoma with secondary aneurysmal bone cyst of the capitate.

Chondroblastoma is a benign tumor that typically arises in the epiphysis of a long bone. There have been only 2 reported cases of chondroblastoma involving the capitate. This is the first report of chondroblastoma with secondary aneurysmal bone cyst involving the capitate. A 33-year-old man presented with a 3-year history of pain and swelling of the right wrist. Radiography as well as computed tomography showed a radiolucent area and no matrix calcification within the capitate. Magnetic resonance imaging revealed a homogeneous signal that was low on T1-weighted images and high on T2-weighted images and showed only slight enhancement. On the basis of imaging findings, the authors chose excisional biopsy. The bone tumor in the capitate was explored through a dorsal approach by dividing the extensor tendons. After repeated curettages, bone graft substitute using allograft bone was packed into the capitate. Histologically, the authors diagnosed this tumor as a chondroblastoma with a secondary aneurysmal bone cyst. At the final 2-year follow-up, there was evidence of bone union, full range of motion, and recovery and no evidence of recurrence. Although the recurrence of chondroblastoma is occasionally reported, the principal treatment is intralesional curettage and bone graft. High-speed burring, phenol, bone cement, and cryosurgery have been reported to reduce local recurrence. Complete excision of the carpal bone seems to be overtreatment.