A case of metastatic struma ovarii treated with 131I therapy: focus on preservation of fertility and selected review of the literature.

Struma ovarii is a rare monodermal ovarian teratoma composed predominantly of mature thyroid tissue. We describe herein the case of a 22-year-old woman who underwent a right salpingo-oophorectomy for struma ovarii at the age of 12 years, who was admitted 8 years later with signs and symptoms of a left pelvic tumor. Laparoscopy detected a left ovarian endometriotic cyst and multiple nodules on the pelvic peritoneum, right lateral abdominal wall, diaphragm, vesical plica and liver. The diagnosis was abdominal and pelvic widespread dissemination of recurrent struma ovarii, with features consistent with the follicular variant of papillary thyroid carcinoma. The patient was treated with a combination of conservative surgery and two 131I administrations (cumulative activity of 350 mCi after dosimetric evaluation). Because of the high degree of hormonogenesis shown by the metastases, the first administration was performed following use of recombinant human (rh) thyroid-stimulating hormone (TSH) to reach adequate TSH levels. To avoid the 'stunning effect' and to obtain high-quality scintigraphy, a whole-body scan was performed with 123I after rh-TSH and before the 131I therapy. We also discuss the potential role and the possible benefit of using gonadotropin-releasing hormone analogs and ovarian tissue cryopreservation to preserve fertility in women treated with 131I for pelvic metastases from malignant struma ovarii.