Papillary Thyroid Carcinoma Arising in a Struma Ovarii: A Case Report and Analysis of Cases Reported in the Literature

Introduction: Struma ovarii is a rare (0.2-1.3%) ovarian teratoma. The true incidence of malignancy is difficult to estimate because of lack of uniform diagnostic criteria, but is said to occur in approximately 5% of cases. There is no standard of treatment. Case Report: Our case was a 36-year-old woman, who was diagnosed postoperatively with malignant struma ovarii: papillary thyroid carcinoma. She underwent left tubal ligation and right salpingo-oophorectomy for adnexal mass. Postoperative metastatic workup revealed a nonmetastatic disease and the patient was not offered any further treatment. The patient is currently followed with serum thyroglobulin and is asymptomatic. We performed a Medline and Embase literature search and analyzed malignant struma ovarii cases documented in the literature since 1970 to 2009, with focus on management. We analyzed 92 eligible reports, including ours, of which 21.7% reported presence of metastasis. Conclusion: Malignant struma ovarii is a rare ovarian neoplasm. We believe that unilateral oophorectomy is a reasonable treatment option in cases when there is no evidence of capsular invasion, vascular invasion, or gross metastasis, and fertility is desired. Adjuvant treatment with total thyroidectomy and iodine-131 ablation is indicated in selected cases. Serial serum thyroglobulin should be used as a tumor marker for follow-up.