Giant cell-rich osteosarcoma of bone

We report here on one case of primary giant cell-rich osteosarcoma of the bone. A 29-year-old female patient with right knee pain showed a geographic purely osteolytic lesion at the proximal metaphysis of the right tibia. There was no detectable matrix mineralization noted on the plain radiographs. MRI showed a well-marginated mass with focal cortical destruction and small soft tissue extensions at the inferior portion of the lesion. The excisional biopsy specimen showed numerous osteoclast-like giant cells, undifferentiated stromal tumor cells with nuclear atypism, and scanty osteoid formation. According to the imaging and pathologic findings, we diagnosed this lesion as a giant cell-rich osteosarcoma. Tumor resection and a limb salvage operation were done, and the patient is now doing just fine with good limb function; she is, without local recurrence or distant metastasis, for the past 11 months since the operation.