Sclerosing stromal tumor of the ovary with elevated CA125

The case is reported herein of an 18‐year‐old woman who developed sclerosing stromal tumor of the ovary. Although she was suspected to have a malignant tumor due to magnetic resonance imaging findings and an abnormal blood CA125 value, the tumor was benign. The immunohistochemical staining by CA125 antibody was negative. She had an uneventful postoperative course, with no postoperative recurrence of the tumor.