EP24.04: Retroperitoneal benign and malignant pelvic masses: presurgical ultrasound diagnosis, histologic and endoscopic correlations

The retroperitoneal pelvic space can contain pathological masses of various origins: organ-related, extra-organ, mesenchymal, lymphovascular, neural, and others. A retrospective, monocentric descriptive study. 3460 adnexal masses and 20 retroperitoneal masses were diagnosed by ultrasound (US) with subsequent diagnostic procedures and surgical treatment during 8 year-period at the gynecological US reference centre (retroperitoneal uterine fibroids were not included in the series). This paper presents US and MRI images alongside endoscopic photo and video files, underscoring the significance of simultaneous evaluation of both modalities for enhancing diagnostic proficiency and competency of the sonologist. The histological variants of peritoneal benign pelvic masses were as follows: fibroma of the bladder, presacral (retrorectal) dermoid teratomas, epidermoid teratoma, retrorectal hamartoma (tailgut cyst), and several types of neural masses (anterior meningocele, Tarlov cyst, schwannoma). The histological variants of peritoneal malignant pelvic masses were as follows: extraperitoneal pelvic extra-organ sarcoma, rhabdomyosarcoma, retroperitoneal extra-organ aggressive angiomyxoma, leiomyosarcoma of the right iliac vein, which appeared as a pelvic lesion. Retroperitoneal pelvic masses exhibit a diverse histological spectrum of anomalies and necessitate multidisciplinary involvement for accurate diagnosis. Frequently, they are misidentified as adnexal masses, highlighting the importance of meticulous preoperative radiological assessment to prevent intraoperative surprises and complications. MRI/CT scans emerge as pivotal diagnostic modalities in this context.