OC25: Sonographic features of abdominal wall endometriotic nodules, a frequently misdiagnosed condition

To describe the clinical and sonographic features of abdominal wall endometriotic nodules. Fifteen women (mean age 36 (range, 30–48)) years, with pathologically proven endometriosis of the abdominal wall were retrospectively recruited during the period between 2001 and 2007. Indications for ultrasound examination were: pain (10 cases, 67%), a palpable mass (seven cases, 47%) and suspicion of umbilical hernia (four cases, 27%). In four cases (27%) the nodule was located on the scar of a previous Cesarean section while in nine (60%) cases it was located at the level of the umbilicus; of these, six patients had a history of laparoscopic surgery for endometriosis. In two women (13%) the nodule was found in the right inguinal canal. Five patients (33%) were asymptomatic, while in 10 cases (67%) cyclic or continuous spontaneous pain was reported. Associated symptoms suggestive of endometriosis were found: dysmenorrhoea in eight (53%) patients, dyspareunia in four (27%) and infertility in five (33%). Sonographically, in all patients the endometriotic nodules appeared as solid hypoechoic masses. Content was inhomogeneous in nine (60%) women; in all cases ill defined margins were found. Pressure exerted with the sonographic probe above the nodule gave pain and helped in the localization. Mean lesion diameter was 20 ( ± 12) mm. The nodule was located above the abdominal wall fascia muscularis in eight cases (53%), below the fascia in two (13%) while in five cases the nodule extended grossly through it. Doppler examination was performed in eight patients: in all cases scarce vascularization of the nodule was found. Hypoechoic nodules of the abdominal wall circumscribed by a hyperechoic rim should raise the suspicion of abdominal wall endometriosis even in patients with no history of endometriosis nor previous laparotomy or laparoscopic surgery. Pushing against the nodule with the ultrasound probe can strengthen such diagnostic suspicion thanks to the pain induced.