<prompt> Struma ovarii is aMetastatic tumorTeratomaSex cord tumorSurface epithelial tumor  <response>: Struma is a river in europe,along its banks endemic goitre was noted. Strauma is loosely used for goitre in europe. A Struma ovarii benign ovarian tumor is a form of teratoma that contains mostly thyroid tissue, which may develop thyrotoxicosis. Source : Bailey and love 26th edition Pg : 748 