Rare case of primary bone lymphoma of the femur

Primary bone lymphoma is a rare type of lymphoma that arises from skeletal tissue. Most cases described are non-Hodgkin's lymphoma with diffuse large B-cell lymphoma being the most common subtype. While it is common for non-Hodgkin's lymphoma to have secondary skeletal system involvement, primary involvement of the skeleton is surprisingly rare. Primary bone lymphoma accounts for less than 5% of all primary bone malignancies, 4%-5% of extranodal lymphomas and less than 1% of all non-Hodgkin's lymphoma. We present an interesting case of a young adult male who was diagnosed with primary bone lymphoma of the femur. Interestingly, his initial X-ray imaging revealed no osseous abnormality and subsequent MRI revealed an infiltrating mass. The patient was treated with chemotherapy of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone resulting in complete remission.