Clear cell chondrosarcoma mimicking chondroblastoma in a skeletally immature patient.

We report the case of a clear cell chondrosarcoma (CCCS) occurring in the femoral head of a 14-year-old skeletally immature boy. Radiographic examination revealed a well-defined, osteolytic lesion in the epiphysis of the femoral head. Given the patient's age and the radiographic appearance of the lesion, chondroblastoma was high on the differential diagnosis. A frozen section was performed at the time of open biopsy was felt to be consistent with either chondroblastoma or CCCS. CCCS in a skeletally immature patient was felt to be unlikely, so curettage and bone grafting was performed. Final pathology review, however, confirmed the diagnosis of CCCS. The patient was taken back to surgery 4 weeks later for a wide resection and hemiarthroplasty.