A rare case of minimally invasive follicular thyroid cancer with intraluminal superior vena cava and right atrium metastases.

Follicular thyroid cancers are known to spread hematogenously to the bones and lungs and rarely presenting with massive angioinvasion. We report a case of a middle-aged female who had undergone total thyroidectomy for minimally invasive follicular thyroid cancer with angioinvasion in 2014. She was noted to have a large tumor thrombus extending from the superior vena cava to the right atrium on whole body scan post-Iodine-131 (131I) remnant ablation therapy. We discuss the various imaging modalities, treatment options, and difficulties in managing such massive angioinvasion in patients with well-differentiated thyroid cancers.