Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging of an isolated subcutaneous loin metastasis from primary papillary carcinoma of the thyroid

Differentiated thyroid cancer frequently metastasizes but generally spreads to regional cervical lymph nodes and, in advanced cases, to the lungs and/or skeleton. Metastases to the skin/subcutaneous tissue are rare. We report 45-year-old male patient presented with a loin swelling which on biopsy showed a papillary carcinoma and referred for fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) to find out the primary disease. PET/CT showed abnormal FDG uptake within a loin metastasis and right lobe thyroid nodule. Fine-needle aspiration from nodule showed papillary carcinoma. Because thyroid cancer can rarely metastasize to the skin, attention should be given to that region during interpretation of the images. He was advised total thyroidectomy and metastasis excision.