“…Herein, we report the level of CA 19–9 can be extremely increased in the case of benign ovarian teratoma without any complications. CA 19–9, also known as cancer antigen 19–9, is a tetrasaccharide carbohydrate that has been suggested as a prognostic tumor marker in patients with pancreatic cancer [ 7 ]. Besides malignancies, CA 19-9 levels may also increase in benign pancreatobiliary, hepatic, and pulmonary diseases; thyroiditis; diabetes mellitus; autoimmune diseases; and gynecologic diseases such as endometriosis and mucinous ovarian tumors [ 7 , 8 ].…”