Subacute Thyroiditis Presenting as a Focal Lesion on [18F] Fluorodeoxyglucose Whole-Body Positron-Emission Tomography/CT

Abstract

A 52-year-old man presented with subacute thyroiditis and showed an intensely hypermetabolic thyroid lesion on 18F-FDG PET/CT. The patient also had coexisting chronic lymphocytic thyroiditis. The lesion of subacute thyroiditis revealed an SUVmax of 9.1 g/mL and was ill-defined, heterogeneous, markedly hypoechoic, and hypovascular on US. Biopsy demonstrated histologic findings of subacute thyroiditis, which should be included in the differential diagnosis of an intensely hypermetabolic thyroid lesion on 18F-FDG PET/CT.