Unusual presentation of 22-kilogram retroperitoneal müllerian serous cystadenoma.

Background: Müllerian cyst of the retroperitoneum is an extremely rare disease that is thought to be a subtype of urogenital cyst. It is a benign condition that can only be diagnosed and cured by surgical resection.

Case: An 80-year-old female with a huge cystic swelling, thought to be ovarian in origin, underwent laparotomy. Surgical exploration and subsequent histopathological analysis of the cyst revealed a müllerian serous cystadenoma of the retroperitoneum, 22 kg in weight. Preoperative ultrasound scan and computed tomography failed to elucidate a correct preoperative etiology.

Conclusion: Huge retroperitoneal cysts may coexist with other pelvic pathology creating diagnostic and therapeutic dilemmas. The use of computed tomography for diagnosis may be not helpful with huge cysts. Good preoperative preparation and surgical technique are essential for managing these cases.