A giant serous cystadenoma developing in an accessory ovary

Background Accessory ovaries are rare anomalies and cysts arising from accessory ovaries are extremely rare. Their reported incidence is 1/29,000–1/700,000. Establishing the diagnosis preoperatively is difficult. Radiologic methods are usually inadequate in recognizing the origin of these tumors. Thus, they are usually confused with other intraabdominal tumors. Case A 22-year-old nulliparous girl presented with abdominal pain and tumoral growth for 1.5 years. Abdominal ultrasound and computed tomography revealed a 33 × 26 × 15 cm cystic mass filling the abdominal cavity. The preoperative diagnosis was a mesenteric cyst. Diagnostic laparotomy revealed a giant cystic mass arising in an accessory ovary. The left tuba and fimbrias were adhered to the cyst. The tumor was totally removed and fimbrioplasty performed. Conclusion In spite of being rare entities, paraovarian anomalies should be considered in the differential diagnosis of intraabdominal tumors, especially when the origin is not identified by radiologic means. Case A 22-year-old single, nulliparious female was admitted to our hospital with abdominal pain, nausea and a growing abdominal swelling since 1.5 years. A tumoral mass was palpated on physical examination. Abdominal ultrasound and computed tomography revealed a 33 × 26 × 15 cm cystic mass filling the abdominal cavity. The origin of the tumor could not be detected. Operation revealed a giant cystic mass arising from an accessory ovary. Histopathologic diagnosis was serous cystadenoma. Conclusion Ovarian or accessory ovarian pathologies must be considered in the differential diagnosis of intraabdominal tumors, especially in young female population.