Primary bone lymphoma with extensive imaging-defined necrosis on magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography: A diagnostic pitfall.

Primary bone lymphoma is an uncommon malignancy, accounting for less than 5% of primary bone neoplasms. Most cases are non-Hodgkin's lymphomas, of which diffuse large B-cell lymphoma is the predominant subtype. On plain radiographs, primary bone lymphoma typically appears as a permeative or moth-eaten pattern of osseous destruction and is often accompanied by an aggressive periosteal reaction. Magnetic resonance imaging typically shows soft tissue extension disproportionate to the degree of cortical destruction. Herein, we describe a diagnostically challenging case in which baseline imaging demonstrated extensive intralesional necrosis, obscuring viable tumors and mimicking osteomyelitis. A definitive diagnosis of diffuse large B-cell lymphoma was established only after repeat, targeted biopsy.