The Role of Radioiodine Therapy in Differentiated Thyroid Cancer Arising from Struma Ovarii: A Systematic Review.

: Struma ovarii (SO) is an ovarian teratoma with the presence of ectopic thyroid tissue. Differentiated thyroid cancer (DTC) in SO is a rare finding. Management of DTC in SO is currently not clearly established. We performed a systematic review of the literature to assess the role of 131I radiometabolic therapy in the treatment of DTC in SO. : a wide literature search in the Scopus, PubMed/MEDLINE, and Web of Science databases was made to find published articles regarding the treatment of patients with DTC and SO. The quality assessment of studies was performed by QUADAS-2 evaluation. : eleven studies were included in the systematic review. All of them were retrospective studies and/or case series, and two of them also included a review of the literature. Most of the studies describe cases of DTC in SO treated by total thyroidectomy (TT) and subsequent radioiodine (RAI) therapy, especially in patients with distant metastases and/or concomitant thyroid cancer. However, the majority of patients apparently did not require radiometabolic therapy. : TT and subsequent RAI therapy is usually performed in metastatic disease, not recommended in patients with intraovarian disease without risk factors, and it appeared possible but not mandatory in patients with risk factors.