Anfelter P, et al. - Researchers conducted a retrospective multicenter-study including 21 patients with a histological diagnosis of ovarian yolk sac tumor in order to determine the clinical and sonographic features of malignant ovarian yolk sac tumors. The collected images and video clips were used for additional characterization by two observers. Pure yolk sac tumor was identified in all cases except in one, who had a mixed tumor (80% yolk sac tumor and 20% embryonic carcinoma). The analysis revealed that often, detection of malignant ovarian yolk sac tumors occurs at an early stage and in young women usually in the second or third decade of life; it presents with pain and markedly elevated serum α-feto protein. Ultrasound images revealed yolk sac tumors is frequently unilateral, large, multilocular-solid or solid, with fine-textured slightly hyperechoic solid tissue, and rich vascularization.