Benign serous cystadenofibroma with multimodal imaging suggestive of malignancy in a symptomatic postmenopausal patient.

Introduction: Adnexal masses in postmenopausal women often present a diagnostic challenge, especially when imaging reveals complex features such as solid components, papillary projections, and ascites. Accurate preoperative characterization is crucial to guide surgical management and avoid unnecessary extensive procedures. Multimodal imaging combined with serum tumor markers and validated risk prediction models such as the IOTA ADNEX (International Ovarian Tumor Analysis) model, enhances diagnostic accuracy in differentiating benign from malignant ovarian lesions. Case presentation: A 49-year-old postmenopausal woman presented to the Emergency Department with severe pelvic pain. Initial evaluation revealed a left adnexal mass with a total size of 13 cm, composed of an 8 cm cystic portion and a 5 cm solid component. Transvaginal ultrasound demonstrated three vascularized papillary projections. Computed tomography and magnetic resonance imaging confirmed the suspicious morphology and ascitic fluid. The preoperative risk of malignancy, calculated using the IOTA ADNEX model via freely accessible online tools, was 81.2%. Due to the severity of symptoms and high suspicion of malignancy, the patient underwent urgent diagnostic laparoscopy. Intraoperatively, the mass appeared partially torsed with external surface papillary excrescences. A left salpingo-oophorectomy was performed, and peritoneal and cystic fluids were collected for cytological analysis. Results: The final histopathology revealed a benign serous cystadenofibroma. Cytological evaluation of the fluids was negative for malignant cells. Postoperative recovery was uneventful. Conclusions: This case highlights the importance of comprehensive diagnostic evaluation in adnexal masses. Even when multimodal imaging and risk models suggest malignancy, benign lesions may mimic malignant features. Integrating clinical, radiologic, and intraoperative findings is essential to avoid overtreatment.