Struma ovarii is a rare ovarian tumor that is composed entirely or predominantly of thyroid tissue. They constitute approximately 3% of all ovarian teratomas, 2% of all germ cell tumors of the ovary, and 0.5% of all ovarian tumors. Only about 5% of struma ovarii is malignant.
Suspicion of struma ovarii arises when a multilocular–solid adnexal mass containing one or more ‘struma pearls’ is seen (Savelli et. al, 2008).




Bibliography
- Savelli, L., Testa, A. C., Timmerman, D., Paladini, D., Ljungberg, O. and Valentin, L. (2008), Imaging of gynecological disease (4): clinical and ultrasound characteristics of struma ovarii. Ultrasound Obstet Gynecol, 32: 210–219. doi:10.1002/uog.5396