Massive ovarian edema is a rare entity that can be confused with ovarian neoplasm. A 20-year-old nulligravid woman presented with a large solid pelvic mass and abdominal mass. On examination a solid mass was found which extended from the pelvis until over the umbilical transversal line. Abdominal ultrasound revealed a solid non-homogenous mass originating from the right ovary with largest diameter of over 30 cm, fine internal echoes, regular margins, and poor vascularization. The abdominal computed tomography (CT) image was non-contributory. Blood work including hematology and biochemistry was normal. There was no sign of systemic infection and the tumour markers are negative. Unilateral adnexectomy was performed during exploratory laparotomy. Histological examination demonstrated massive ovarian edema. The adnexa weighted 1,585 g. Massive edema of the ovary remains difficult to diagnose before surgery because it may clinically and radiologically mimic an ovarian neoplasm. The majority of cases present with recurrent abdominal pain or a palpable adnexal mass. Nausea with or without vomiting can be present. Menstrual irregularities are common. Some patients have signs of masculinization including hirsutism, clitoromegaly, voice deepening, precocious puberty. However, this entity should be considered in young women presenting with an ovarian mass and abdominal pain. Treatment of massive ovarian edema is controversial.