Lethal, Malignant, Metastatic Struma Ovarii

Background: Struma ovarii (SO) is extremely rare, with less than 200 reported cases in the medical literature. SO is defined by the presence of an ovarian tumor containing thyroid tissue as the predominant cell type. Malignant transformation is rare and lethal cases of SO are even rarer. We report on a patient presenting with left ovarian cystic SO and lethal outcome. Summary: A 45-year-old woman was diagnosed with a follicular variant of papillary carcinoma on laparotomy and left salpingo-oophorectomy. She had persistently elevated serum thyroglobulin following total thyroidectomy + radioiodine and second-look surgery. Imaging scan analysis showed pelvic tumor recurrence and hypervascular liver metastases during follow-up as well as peritoneal carcinomatosis in the pelvis, right abdominal wall, and malignant ascites. The patient died from cachexia at 37 months after diagnosis. Conclusions: Such an aggressive malignant disease and lethal course of SO is rare. Total thyroidectomy is mandatory to exclude a primary thyroid neoplasm and for radioiodine therapy and follow-up. SO may spread to contralateral ovary, pelvic nodes, peritoneum, liver, lungs, and bones through hematogeneous spread, which is different from the dissemination pattern of papillary thyroid carcinomas. Imaging highlights the mixed behavior of this ovarian tumor.