Asymmetric diffuse thyroid uptake on 18F-FDG PET/CT in patient with subacute thyroiditis: Case report and literature review.

A 48-year-old man with an intermittent fever of 39.0oC for more than three weeks underwent computed tomography (CT) and blood testing, which revealed no clues. Antibiotics wereadministered, but his condition did not improve. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) showed right-lobe-dominant diffuse thyroid uptake. On technetium-99m (99mTc) pertechnetate scintigraphy, the thyroid gland could not be visualized, and he was diagnosed with subacute thyroiditis (SAT). When asymmetric 18F-FDG diffuse thyroid uptake on PET/CT is observed in a patient with a fever of unknown origin (FUO), SAT may need to be considered.