Purpose: Ovarian cancer presents as an acute abdomen very rarely. The purpose of the study is the description of a right ovarian malignant dysgerminoma presenting as an abdominal emergency. Case: A 16-year-old white female presented with acute abdominal pain in the right iliac fossa. On physical examination the abdomen was acute and a mass in the right lower abdomen was palpated. The patient was sexually active and bimanual gyneco­logical examination revealed the presence of a large lobulated solid tumor in the position of the right adnexa. Ultrasound examina­tion showed the presence of a large, multilobulated, heterogeneous, predominantly solid pelvic mass. Color flow imaging showed intratumoral flow signals. The uterus and the left ovary had normal size and echo-texture. Fluid was found in the cul-de-sac and in Morisson’s space. An immediate exploratory laparotomy exposed the presence of a twisted right ovarian mass and intraperitoneal hemorrhage. A superficial tumoral vessel actively bleeding was seen. Peritoneal fluid was obtained for cytology. The intra-abdom­inal hemorrhage ceased when the ovarian pedicle was clamped. The patient underwent right salpingo-oophorectomy and biopsy of the omentum. Pathologic analysis revealed a malignant dysgerminoma of the right ovary, expanding to the mesosalpinx. Cytology was positive for malignancy. Postoperative CT scan of the upper and lower abdomen was negative. The patient was assigned to FIGO Stage UC and referred for platinum-based chemotherapy. Conclusion: Ovarian malignant dysgerminoma may present as an acute abdomen because of torsmn, passive blood congesuon, rupture of superficial tumoral vessels and subsequent intra-abdominal hemorrhage. Ovarian dysgerminoma should be part of the differential diagnosis in a young woman with acute surgical abdomen and a solid heterogeneous pelvic mass detected by ultra­sonographic scan.