Dual Tracer Imaging Revealing Rare Case of Giant Cell Tumor in Polyostotic Fibrous Dysplasia

Abstract

A 31-year-old man with known polyostotic fibrous dysplasia (FD) presented with progressive right wrist swelling. Imaging with fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) demonstrated multiple FDG-avid skeletal lesions consistent with FD, along with an additional morphologically distinct FDG-avid soft-tissue lesion in the right wrist lacking typical intramedullary characteristics. Although the metabolic activity of this lesion was comparable to other FD lesions, its atypical morphology raised suspicion of a superimposed pathology. Histopathological evaluation confirmed giant cell tumor (GCT) of bone. Subsequent 99mTc-sestamibi scintigraphy demonstrated tracer uptake confined to the wrist lesion, with no uptake in FD lesions, indicating differential tracer behavior. The coexistence of FD and GCT is exceedingly rare and poses a diagnostic challenge, particularly in the setting of overlapping metabolic imaging findings. Here, we present a rare case of concomitant FD with GCT.