Mucosal Prolapse Polyp Mimicking Rectal Malignancy: A Case Report

Mucosal prolapse syndrome mimicking Peutz-Jeghers syndrome in a pediatric patient

Mucosal prolapse syndrome (MPS) is a rare group of benign conditions characterized by a set of unifying histologic findings thought to be the result of repeated mucosal shearing and submucosal vascular congestion caused by straining. This set of conditions is often misdiagnosed as other polyposis syndromes, inflammatory bowel disease, or malignancy due to its clinical presentation, appearance, and rarity. We report a case of a 15-year-old male who presented with painless rectal bleeding. He was found to have four rectal polyps thought to be due to Peutz-Jeghers syndrome. A repeat colonoscopy with biopsies a year later revealed a diagnosis of MPS. Our case highlights the morphologic similarity between hamartomatous polyp and mucosal prolapse histology. Since MPS is a rare diagnosis even among the adult population, it has not been well described in pediatrics. This syndrome should be on the differential diagnosis for pediatric rectal polyps to prevent unnecessary invasive testing and a delay in treatment.

Incidentally Discovered Mucosal Prolapse of the Colon During Colorectal Cancer Screening: A Case Report

Colonic mucosal prolapse syndrome is a rare type of non-neoplastic non-inflammatory colorectal polyps that can mimic neoplastic lesions. We present a case of a 65-year-old man with mucosal prolapse syndrome, incidentally, discovered during colorectal cancer screening. The patient was asymptomatic, and his physical exam and laboratory test results were unremarkable. During a colonoscopy, the physician removed three small tubular adenomas and two pedunculated polyps suspicious of neoplasms. Retroflexion revealed small internal hemorrhoids. The histology of the larger polyps revealed mucosal prolapse features, while the smaller polyps displayed features consistent with tubular adenomas. Management involves the removal of associated polyps during colonoscopy, followed by surveillance colonoscopy to detect any recurrent polyps or early signs of colorectal cancer. Accurate diagnosis is crucial to avoid unnecessary interventions and ensure appropriate management.

Rectal mucosal prolapse with an emphasis on endoscopic ultrasound appearance

AIM

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Prolapsing mucosal fold: largest reported, presenting with major haemorrhage

Prolapsing mucosal folds are uncommon benign colonic lesions that when inflamed may macroscopically resemble, and be confused with, an adenomatous or hyperplastic polyp. They are usually small and rarely cause symptoms. We report the case of a 55-year-old female admitted to hospital following six episodes of significant rectal bleeding. A colonoscopy revealed a 45 × 12 × 5 mm³ pedunculated polyp in the sigmoid colon. There was no evidence of haemorrhoids, colitis or diverticulosis. The polyp was resected by electrosurgical snare at 40 cm and a resolution clip was used to prevent postoperative bleeding. Histology of the polyp demonstrated a polypoid prolapsed mucosal fold with a core of fibrovascular submucosal tissue and normal overlying mucosa. In an extensive review of available literature, no polyp of this size has been reported.

Rectal ischemia causes mass formation, masquerading as rectal cancer

Rectal ischemia rarely occurs because of the rich vascular supply of the rectum, while endoscopic presentation of ischemic colitis always is not distinct and can uncommonly mimic malignant neoplasm. We present a case of a rectal ischemia, which presented with haematochezia and proctoscopy revealed a large ulcerating mass, masquerading as rectal cancer and obstructed the lumen of rectum. However, histological examinations showed only features for ischemic colitis and no evidence for malignancy. The patient was treated conservatively and 10 days later, new endoscopy showed complete disappearance of ulcerated mass, and new biopsies confirmed the initial diagnosis. Awareness and early diagnosis of ‘mass forming’ entity of ischemic colitis is very essential in order to carry out appropriate treatment and avoid severe complications.