Unusual Dual Complications: Bowel Obstruction and Hydronephrosis Secondary to a Large Ovarian Serous Cystadenoma in a Postmenopausal Patient.

Ovarian cystadenomas are common benign tumors that are typically detected early; however, some patients develop large, symptomatic masses. We report the case of a 72-year-old postmenopausal woman who presented with a two-week history of abdominal pain, nausea, vomiting, and right lower quadrant abdominal fullness. The patient had previously undergone hysterectomy and bilateral oophorectomy. CT imaging revealed a large, multi-loculated pelvic mass (19.3 × 17.4 cm) causing small bowel obstruction and right hydroureteronephrosis. An exploratory laparotomy was performed, and histopathological examination confirmed an ovarian serous cystadenoma. This case highlights that even benign ovarian lesions can lead to significant complications, underscoring the need for a multidisciplinary approach with the support of comprehensive imaging and meticulous surgical planning.