Pulmonary metastasis of struma ovarii: a case report

We report the case of a 42-year-old woman who presented with multiple pulmonary nodules. Surgical resection of 3 nodules revealed differentiated thyroid carcinoma. Thyroid and neck ultrasound was normal. A review of her history revealed that this patient underwent an ovarian cyst resection 15 years ago. Reexamination of pathology samples, with the help of immunohistochemical markers, concluded to a struma ovarii. Pelvic ultrasound was normal; F-18 FDG PET scan was negative. She had total thyroidectomy, with negative histology, followed by first I-131 therapy (3.9 GBq). Thyroglobuline (Tg) was elevated (3230 microg/L in hypothyroidism). The whole-body scan showed multiple foci of pulmonary I-131 uptake, a bone metastasis of third rib, and I-131 uptake in an abdominal para-aortic lymph node. At second I-131 therapy (3.8 GBq), Tg level had decreased to 14 microg/L and there was a decrease in the number of pulmonary nodular I-131 uptake, and resolution of the bone and para-aortic lymph node metastasis. At third I-131 therapy (4.9 GBq), thyroglobuline was undetectable and the whole-body scan showed no I-131 uptake. Struma ovarii is a rare ovarian tumor mostly benign. Metastasis of malignant struma ovarii are rare. Most frequent localizations are liver and peritoneum. Treatment of the malignant struma ovarii implies ovarian surgical resection, total thyroidectomy, and I-131 therapy.