The hypermetabolic giant: 18F-FDG avid giant cell tumor identified on PET-CT.

An 87 year-old white female presented with a two-year history of intermittent discomfort in her left foot. PET-CT identified intense18F-fluorodeoxyglucose (FDG) uptake corresponding to the lesion. Histology of a fine needle aspiration and open biopsy were consistent with a benign giant cell tumor (GCT) of the bone. GCT of bone is an uncommon primary tumor typically presenting as a benign solitary lesion that arises in the end of the long bones. While GCT can occur throughout the axial and appendicular skeleton, it is exceedingly uncommon in the bone of the foot. While 18F-FDG has been established in detecting several malignant bone tumors, benign disease processes may also be identified. The degree of 18F-FDG activity in a benign GCT may be of an intensity that can be mistakenly interpreted as a malignant lesion. Therefore, GCT of the bone can be included in the differential diagnosis of an intensely 18F-FDG-avid neoplasm located within the tarsal bones.