Rectum, Penile, Brain and Bladder, Consecutive Rare Distant Metastasis in Two Patients With Papillary Thyroid Carcinoma: Case Reports

Papillary thyroid carcinoma (PTC) has a favorable prognosis. However distant metastases seldom occur and negatively impact patient outcomes. To our knowledge, this is the first report of PTC metastasizing to the rectum, penis, and bladder. We report 2 patients having PTC with metastases to previously unreported sites. The first male patient had PTC with metastases to the rectum and penis, in addition to lung, liver, spleen, and skeletal muscle involvement at the time of initial diagnosis. Surgical pathology reported classic PTC with clear cell features and infiltrative follicular variant. The second female patient had PTC with aggressive lateral neck lymph node metastases at initial surgery. Surgical pathology reported PTC having tall cell variant with rhabdoid components. Subsequent metastases to bladder, lung, brain, vertebrae, and sternum occurred within 2 years. These cases emphasize the importance of early suspicion and thorough evaluation, particularly in aggressive subtypes, as timely detection may improve treatment strategies and patient outcomes. Due to the lack of established guidelines for rare metastatic sites, additional case reports are essential to guide diagnosis and treatment.