Use of F-2-deoxy-2-fluoro-D-glucose positron emission tomography/computed tomography for staging thyroid carcinoma in a cat.

Thyroid nodules are common in older cats and are mostly benign; however, carcinomas may occur infrequently. In cats, thyroid carcinomas tend to be highly metastatic. The role of F-2-deoxy-2-fluoro-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in human thyroid carcinoma has been well established. However, guidelines have not yet been established for veterinary medicine. Metastasis assessment has typically been performed using CT in veterinary medicine; however, it is poorly sensitive in detecting regional lymph nodes or distant metastases if these lesions are not abnormally contrast-enhanced, enlarged or cause overt mass effects. This case suggested that FDG PET/CT may be used for staging feline thyroid carcinoma, and the results contributed to treatment recommendations.