An unusual variant of malignant struma ovarii.

Struma ovarii is a highly specialised form of mature ovarian teratoma. When thyroid tissue constitutes 50% or more of the ovarian neoplasm, the tumour is termed struma ovarii. Malignant struma ovarii is rare and makes up 0.1-0.3% of all ovarian teratomas [2]. We describe a case of follicular variant of papillary carcinoma arising from struma ovarii with elevated CA-125 and pseudo-Meig syndrome.