[Show abstract][Hide abstract]ABSTRACT: Cystadenofibromas are rare benign or borderline malignant neoplasms containing both epithelial and stromal components. We report a case of endometrioid cystadenofibroma in a patient with endometriosis. In this case, the solid component showed very high signal intensity on T2-weighted images and was enhanced after Gd-DTPA administration, reflecting marked stromal edema of fibrous tissue. Endometrial cysts with malignant transformation are reported to have an enhancing solid component and to show various intensities on T2-weighted imaging. However, a solid component showing very high signal intensity on T2-weighted images should also be considered stromal edema in benign or borderline cystadenofibromas.