Follicular thyroid carcinoma metastasizing to rare sites and exhibiting variable inter-lesional heterogeneity on F-fluorodeoxyglucose positron emission tomography/computed tomography and I.

A patient of differentiated follicular thyroid carcinoma with unusual sites of metastases is illustrated with I and F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) imaging findings. The described case harbored extremely rare metastasis to the urinary bladder with multi-organ metastatic disease (including unusual sites of right bronchus and hepatic metastases). There was inter-lesional heterogeneity among the metastatic lesions with regard to the I and FDG uptake in the aforementioned lesions. The detection of such heterogeneity has important implications for patient management in metastatic differentiated thyroid carcinoma.