Soft tissue metastases from differentiated thyroid cancer diagnosed by ¹⁸F FDG PET-CT.

Distant metastases of differentiated thyroid cancer are unusual; lung and bones are the most frequently affected sites. Soft tissue metastases (STM) are extremely rare. We describe two cases of patients with differentiated thyroid cancer metastasizing to soft tissues. Both patients had widespread metastatic disease; clinically asymptomatic soft tissue metastases were found by ¹⁸-Fluordeoxyglucose positron emission tomography/computed tomography (¹⁸F FDG PET-CT), and confirmed by cytological and/or histopathological studies. These findings underscore the ability of ¹⁸F FDG PET-CT in accurately assessing the extent of the disease, as well as the utility of the method to evaluate regions of the body that are not routinely explored.