OC26.01: Do the ultrasonographic features of rectosigmoid endometriotic nodules allow predicting the depth of infiltration of endometriosis in the intestinal wall?

To assess if the ultrasonographic features of rectosigmoid endometriotic nodules allow predicting the depth of infiltration of endometriosis in the intestinal wall. This study included patients who had ultrasonographic diagnosis of rectosigmoid endometriosis and underwent segmental bowel resection. Based on ultrasonography, the rectosigmoid nodules were classified as follows: type 1: nodules with regular outline; type 2: nodules with a progressive narrowing as a “tail”; type 3: nodules with prominent “spikes” towards the bowel lumen; type 4: nodules with prominent “spikes” towards the bowel lumen and a progressive narrowing as a tail; type 5: nodules with extrinsic retraction and negative “sliding sign”; type 6: nodules with prominent “spikes” towards the bowel lumen, extrinsic retraction and negative “sliding sign”. The ultrasonographic features of the nodules were compared with histology. 123 patients were included in the study; their mean (±SD) age was 32.8 (±4.6) years. The length of the resected bowel segment was 11.3 (±2.4) cm. The deeper nodule infiltrated the intestinal muscularis propria in 66.7% of the patients, the submucosa in 20.3% and the mucosa in 13.0%. Type 3 and 4 nodules were more frequently associated with the infiltration of the submucosal/mucosal layer than other types of nodules (p < 0.001); however, no type of nodule always infiltrated the submucosal/mucosal layer. Independently from the type of nodule, the performance of ultrasonography in diagnosing submucosal/mucosal layer infiltration was sensitivity 78.1%, specificity 87.8%, positive predictive value 76.2%, negative predictive value 88.9%, positive likelihood ratio 6.4% and negative likelihood ratio 0.25%. Ultrasonography has good diagnostic performance in detecting infiltration of the submucosal/mucosal layer that is more often associated with type 3 and 4 nodules.