Primary lymphoma of bone in the femur complicated by a fracture and listeria osteomyelitis.

We present a case of primary diffuse large B-cell lymphoma of bone accompanied by osteomyelitis, which was challenging to diagnose. CT revealed no distant metastases; thus, primary bone tumour and osteomyelitis were included in the differential diagnosis. A needle biopsy of an extraosseous lesion found no malignancy, and granulation tissue with abscess formation was pathologically diagnosed. An incisional biopsy was performed to assess osteomyelitis. A culture grew Listeria monocytogenes, but malignant lymphoma was diagnosed based on a pathological analysis of an open biopsy specimen. Imaging studies demonstrated diffuse, intrafemoral spread of the tumour. However, the extent of the spread of the lymphoma and osteomyelitis was unclear. Hip disarticulation was performed to eradicate the infection, and chemotherapy was administered. Primary lymphoma of bone is difficult to differentiate from an infection on imaging studies, and its co-occurrence with osteomyelitis at the initial presentation, as in this case, is extremely rare.