Abstract Background Rectal mucosal prolapse syndrome (RMPS) is a benign disorder frequently misdiagnosed as inflammatory bowel disease (IBD) due to the nonspecific clinical signs and varied endoscopic features. This misdiagnosis often leads to unnecessary and ineffective IBD-specific treatments. We aimed to characterize the clinical, endoscopic, and histological features of RMPS to aid in its distinction from IBD. Methods This retrospective study included 25 patients diagnosed with RMPS at a tertiary referral center (2020–2025). Diagnosis was validated by a multidisciplinary team of gastroenterologists and pathologists. Data on demographics, symptoms, endoscopy, histology, and prior misdiagnoses were analyzed. Results The cohort had a male predominance (72%), with a mean age of 33.9 years. Common symptoms included hematochezia (64%), constipation (40%), mucous stool (28%), and rectal prolapse (16%). Prior misdiagnoses included ulcerative proctitis (40%), rectal tumors (16%), Crohn’s disease (12%), and polyps (12%). Some patients received inappropriate therapies (e.g., corticosteroids, surgery) before the correct diagnosis. Endoscopically, lesions were typically located 3-10 cm from the anus, predominantly on the anterior wall (64%). Morphologic patterns included mucosal polyps (40%), ulcers (28%), hyperemic mucosa (16%), and mixed types (16%) (Figure 1). A white pseudomembrane was observed in 76% of cases. Histology revealed fibromuscular obliteration of the lamina propria in 68% (Table 1). Conclusion RMPS is a prevalent but underrecognized mimic of IBD. Distinguishing RMPS from IBD is critical to prevent prolonged, ineffective medical therapy. Recognizing key features, such as anterior wall involvement, pseudomembranes, and obliteration of the fibromuscular lamina propria, is crucial for accurate diagnosis and the avoidance of unnecessary treatments. A high index of suspicion for RMPS should be maintained in patients with distal rectal lesions who are unresponsive to standard IBD treatment. Conflict of interest: Ms. Li, Zhaoyang: No conflict of interest Axi, Libumu: No conflict of interest Chen, Xiao-Ting: No conflict of interest Xu, Hongzhen: No conflict of interest Luo, Mengqi: No conflict of interest Zhong, Rui: No conflict of interest Zhang, Qiuyue: No conflict of interest Wang, Yufang: No conflict of interest
Li et al. (Thu,) studied this question.