A Rare Case of Functional Ectopic Hyperthyroidism: Struma Ovarii

Struma ovarii (SO) is a rare special type of monodermal teratoma of ovary that predominantly consists of thyroid tissue (> 50%). In only 5 to 20% of cases hyperthyroidism is seen due to functional SO. We are reporting here a case of unilateral benign cystic SO in a 50-year-old postmenopausal lady presented with pain and heaviness in lower abdomen without any signs and symptoms of hyperthyroidism. Pelvic ultrasonogram showed right side tubo-ovarian mass and was planned for laparotomy. In preoperative investigation subclinical hyperthyroidism was diagnosed. Abdominal exploration showed cystic mass lesion in right ovary. She underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histopathological examination diagnosed the mass as benign cystic SO. Patient became euthyroid after surgical removal of tumor.