Struma ovarii is a rare form of ovarian neoplasm in a form of mature teratoma and is composed predominantly of thyroid tissue. In the literature review, there has only been 10 cases of this tumor, associated with ascites and pleural effusion (Meig's Syndrome) and increased CA125 so far. In such cases, the tumor mimics malignant ovarian tumor. In this article, the case of a 72-year-old symptomat...