[Primary osseous lymphoma with pathological fracture during therapy].

A 66-year-old woman was aware of a cervical tumor in May 2007. She was hospitalized in June 2007 because her cervical tumor had increased. A biopsy was performed and a diagnosis of CD20-positive diffuse large B-cell lymphoma was obtained. Ga-67 scintigraphy showed abnormal accumulation in the right clavicle, right femur, right knee joint, right ankle joint, and the left tibia and fibula; however, no abnormality was detected on plain radiography and CT scan, whereas MRI showed that the right femur had a low signal on the T1-weighted image, and high and low signals on the T2-weighted image. CHOP therapy was begun, and the right cervical tumor promptly reduced. She was administered rituximab seven days after initiation of the treatment. When standing up from the toilet at midnight, she suffered fractures of the left tibia and fibula, and the right neck of the femur. These regions were identical to the sites with abnormal accumulation on Ga-67 scintigraphy, so we supposed them to be chemotherapy-associated pathologic fractures. This case is reported because primary bone lymphoma is rare and followed an unusual course of pathologic fracture under treatment.