Bone Marrow Necrosis with Underlying Skeletal Lymphoma Evaluated by ¹⁸F-FDG PET/CT and MRI

Bone marrow necrosis (BMN) is usually associated with malignancies and is characterized by multiple geographic signal abnormalities on magnetic resonance imaging (MRI). We report a 28-year-old female with BMN and underlying diffuse large B-cell lymphoma. Diffuse abnormal signal intensities through the vertebral column were demonstrated on her pretreatment MRI, and the diagnosis of BMN was challenging. Positron emission tomography/computed tomography (PET/CT) for lymphoma staging showed multiple decreased or absent ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake within the vertebrae and pelvis. Marrow biopsy pathological examination showed lymphoma infiltration and massive necrosis. On the follow-up MRI obtained approximately 21 months after the PET/CT scan, multiple geographic abnormal signal intensities were detected within the vertebral column and were consistent with the areas of decreased ¹⁸F-FDG uptake on PET/CT. This case indicates that ¹⁸F-FDG PET/CT is helpful in the diagnosis of BMN with atypical MRI appearances.