Endocrine Abstracts

Introduction: Struma ovarii is a rare condition which elicited considerable interest because of its many unique features like its relationship to teratoma and differentiated thyroid cancer. The most common thyroid carcinomas to arise in struma ovarii are papillary and follicular.

Objectives: We describe two patients with differentiated thyroid carcinoma originating from malignant struma ovarii.

Results: Our index patient is a 32-year-old woman with well differentiated follicular carcinoma who developed peritoneal dissemination and appendix tumoural infiltration of a follicular variant of papillary thyroid carcinoma arising from an ovarian teratoma. There was no thyroid carcinoma within thyroid tissue (total thyroidectomy). Whole body scintigraphy (WBS) with therapeutic activity of I-131 (two sessions; cumulated activity: 300 mCi) revealed disseminated pulmonary and bone metastases with a complete response after radioiodine therapy. The second patient is a 49-year-old woman presenting with bone pain revealing bone follicular thyroid carcinoma metastases on biopsy; total thyroidectomy with lymphadenectomy was performed revealing a follicular thyroid carcinoma T3N1bM1. Two years later, ovarectomy revealed a malignant struma ovarii. Surgical spinal decompression and resection of several vertebral metastases as well as seriate adjuvant radioiodine therapy (279 mCi I-131) were performed. WBS revealed high uptake on cervical lymph node and disseminated pulmonary and skeleton metastases justifying the pursue of radioiodine therapy.

Conclusions: Vascular invasion of the thyroid carcinoma within struma ovarii was not identified in any of the cases; however, disseminated metastases were identified. Mechanisms still need to be searched for. At present, treatment for patients with thyroid carcinoma within ovarian malignant struma ovarii comprises resection of the extraovarian tumoral tissue with subsequent thyroidectomy followed by radioactive iodine ablation.