P18.09: Retzius' retroperitoneal bladder endometriosis: a new entity of an enigmatic disease

To report Retzius' space retroperitoneal bladder deep infiltrating endometriosis (DIE), a new and unusual anatomic site which makes challenging both the diagnosis than the surgical treatment. Consecutive fertile women with DIE complaining endometriosis-related urinary symptoms were prospectively enrolled. 3D- transvaginal sonography (TVS) was performed in all patients with the GE Voluson E8 unit, using a wide-band 3-9 MHz transducer. 3D-TVS was performed with a properly strict methodology as diagnostic tool, based on a properly mid-filled bladder volume (100-150 mL). VCI analysis by 2mm slices of the stored 3D multiplanar examinations was considered for the evaluation of bladder nodules. Surgery was based on laparoscopic management of retroperitoneal bladder DIE, medical treatment on continuous oral contraceptives (COC). Demographic, medical, imaging and surgical data were recorded. Eight patients were enrolled. Median age was 34 years (range 24-43) years. Retroperitoneal bladder endometriotic nodules typically appear as ventral smooth, hypoechoic, homogeneous oval-shaped lesions. Laparoscopic surgery, performed in two cases, showed negative peritoneal findings, with the need to approach to the Retzius space in combination with a transurethral endoscopic approach and/or transrectal sonography to intra-operatively identify otherwise macroscopically normal appearance bladder wall. Medical therapy by COC permitted to control pain in most of symptomatic patients. 3D-TVS confirmed to be the standard technique to investigate patients complaining DIE-related urinary symptoms. Laparoscopic surgery might be incomplete because of negative peritoneal findings. A combined transurethral endoscopic and/or transrectal sonographic approach is a safe and easy technique for the management of Retzius' space retroperitoneal bladder DIE, with low risks and good resolution of symptoms.