Unusual Diffuse and Heterogeneous FDG Uptake in Appendicular Bone Marrow Space in a Patient with Acute Lymphoblastic Leukemia.

We describe a case of F-18-2-fluoro-2-deoxyglucose (FDG) uptake in the appendicular bones on a positron emission tomography/computed tomography (PET/CT) scan in a 20-year-old woman with a diagnosis of acute lymphoblastic leukemia. An FDG PET/CT was performed on this patient because of fever of unknown origin, revealing diffuse and heterogeneous FDG uptake in the bone marrow space of both humeri, femurs, and tibiae. The patient underwent magnetic resonance imaging, which demonstrated bone infarction with heterogeneous high, intermediate, and dark signal intensities on T1- and T2-weighted images in the same areas.