A case of a giant Struma ovarii associated with Hyperthyreosis

20-25% of ovarian neoplasms are germ cell tumors and the majority of them account for mature teratomas. Thryroid tissue is a common finding in ovarian teratomas (>50%), the term struma ovarii (SO) is dedicated to ovarian neoplasms that either entirely or predominantly (>50%) consist of thyroid tissue, which accounts for 1-3% of all ovarian teratomas. SO associated with hyperthyreoidisms is a very rare complication.

Case report A 52-year-old women presented with abdominal pain and a history of bowels resection because of neuroendocrine carcinoma years before. Clinical examination presented a large ovarian tumor, suspicious for malignancy and a serum level of Ca-125 of 80 U/ml. The resection specimen presented an ovarian tumor of 763 g and 16,0 × 9,5 × 9,5 cm with multicystic brownish cutting surface with cysts ranging from 0.2 up to 8.5cm. The tumor was initially misdiagnosed as suspicious for endometrial ovarian carcinoma on frozen section, but diagnosed as benign SO on final sections which was confirmed by immunostaining. During follow up, the patient presented with hyperthyreoidisms and thrombosis of the V. brachialis six weeks before. The signs of hyperthreoidism disappeared after tumor resection.

Discussion Usually, SO present with non-specific symptoms, such as abdominal pain /distension, vaginal bleeding or it is an incidental finding in patients with pelvic discomfort. A few patients have ascites or ascites with hydrothorax (pseudo-Meigs syndrome). Ectopic hyperthyreoidism caused by SO is extremely rare. The case demonstrates an unusual large benign SO, causing ectopic hyperthyreoidism, which was initially misdiagnosed as ovarian cancer on frozen section.

Publication History

Article published online:
10 June 2022