Malignant Struma Ovarii Presenting as a Vaginal Mass

Abstract

Malignant struma ovarii encompasses a spectrum of conditions ranging from struma ovarii with microscopic, clinically unimportant papillary carcinoma to cases of struma ovarii with papillary or follicular carcinoma that have metastasized. Recently it has been proposed that highly differentiated follicular carcinoma arising in struma ovarii may resemble non-neoplastic thyroid tissue both in the ovary and at sites of dissemination and metastasis. We report a unique case of a struma ovarii with non-neoplastic appearing thyroid tissue which presented 6 years later as a vaginal metastasis of a typical thyroid-type follicular carcinoma. The present case adds to the spectrum of rare primaries metastasizing to the vagina.