Monomorphic teratoma of the ovary: a rare cause of triiodothyronine toxicosis.

A case of low thyroid radioactive iodine uptake (RAIU) thyrotoxicosis due to a large struma ovarii comprising pure thyroid tissue is presented, including a detailed diagnostic evaluation, histopathology, and demonstration of rapid recovery of native thyroid function after surgical excision. In addition, the first comprehensive analysis of thyroglobulin obtained from an ovarian struma is reported.