Rectal mucosal prolapse with an emphasis on endoscopic ultrasound appearance

The diagnosis of mucosal prolapse syndrome (MPS) continues to be a challenge. Endoscopic ultrasound (EUS) is of clinical value in anorectal diseases. This study seeks to investigate the use of EUS in the diagnosis of MPS.A total of 39 patients diagnosed with MPS between June 2015 to December 2019 were included in this study. Their clinical histories, endoscopic images, EUS images, and pathological data were retrospectively collected, and the EUS images were reviewed to summarize the characteristics of MPS.In total, 39 MPS patients were enrolled. The main presenting symptoms were bleeding (61.5%) and constipation (53.8%). Gross appearance of the rectal lesions was mainly classified into three types: 51.3% of the lesions were polypoidal/nodular, 33.3% were ulcerative and 15.4% were flat with erythematous mucosa only. A total of 10 patients underwent EUS operation. With regard to the EUS appearance of MPS, four patients with polypoidal/nodular lesions showed thickening of the mucosa on EUS. The diffuse thickening of the mucosa-submucosa layer and disappearance of the architectural structure was observed in four patients with ulcerative lesions. Finally, the thickening of the muscularis propria was observed in two flat lesions. The serosal layers were intact in all the MPS patients. Neither blood flow signals nor regional lymph nodes were observed on EUS.The EUS characteristics for MPS corresponding to different gross appearance can be classified into three types. These findings suggest that EUS is useful in the diagnosis of MPS.