Follicular carcinoma of the thyroid appearing as an intraluminal superior vena cava tumor.

Follicular carcinoma of the thyroid has the propensity for microscopic angioinvasion. Tumor extension into the great veins has been previously reported primarily as a postmortem finding. Most patients have a long history of a substernal goiter and appear initially with superior vena cava syndrome. We studied a case of intraluminal invasion of the superior vena cava by a follicular carcinoma of the thyroid, without superior vena cava syndrome. To our knowledge, this is the second reported case of a patient treated successfully by surgery.