ODP449 A Case of Malignant Struma Ovarii

A 45 year old female presented to the ER with pelvic pain. Ultrasound of the uterus revealed a left ovarian 8 cm dermoid cyst. She underwent a unilateral salpingo-hysterectomy. During the operation, no high risk features were seen including no ascites or adhesions. Final pathology revealed a 2.2 cm papillary thyroid cancer with no other worrisome features (no angio-invasion or lymphatic invasion). A diagnosis of malignant struma ovarii was made, and the patient was referred to endocrinology for further work up. A neck US was performed revealed a benign looking, partially cystic, 0.8 cm right thyroid nodule. An FNA attempted came back non-diagnostic. Thyroid functions and baseline thyroglobulin were normal. The clinical dilemna that came up was how to approach the thyroid gland status since in the majority of thyroid cancer cases, the thyroid gland is removed. On review of over 200 cases reported in the literature of localized malignant struma ovarii, the majority of the cases were treated with pelvic surgery alone, and the thyroid gland was left in place. There is no available data that removing the thyroid gland in these patients decreases the risk of recurrence of thyroid cancer. Given the lack of any high risk features in our patient, it was decided not to pursue further adjuvant treatment and to continue surveillance with a repeat of thyroglobulin level in 6 months. Presentation: No date and time listed