Mucosal prolapse syndrome presenting as rectal polyposis

Podoplanin Expression in Early-Stage Colorectal Cancer-Associated Fibroblasts and Its Utility as a Diagnostic Marker for Colorectal Lesions

(Background) Cancer-associated fibroblasts (CAFs) are major cancer stromal components. CAFs have diverse functions and cell origins. Podoplanin (PDPN), a lymphatic vessel marker, is also a CAF marker in certain cancers. On daily diagnosis of early colorectal carcinoma (CRC), PDPN upregulation in the stroma is often encountered, suggesting PDPN-positive CAFs have emerged. However, PDPN-positive CAFs in early CRC have not been studied well. (Methods) On immunohistochemistry, PDPN expression in the lamina propria or stroma of adenomas, early CRCs, and neuroendocrine tumors, their normal neighbors, and non-neoplastic colorectal lesions were compared. Single-cell RNA sequencing (scRNA-seq) of CRC was used to explore PDPNhigh CAFs' cell origins. (Results) Reticular cells or pericryptal fibroblasts in the lamina propria of adenomas and early CRCs showed higher PDPN expression than did normal mucosae and non-neoplastic lesions (p < 0.01). Pericryptal PDPN expression was a diagnostic feature of adenomas and early CRCs. scRNA-seq of CRCs highlighted that PDPNhigh CAFs had distinctly higher COL4A1, COL4A2, and WNT5A expression, unlike well-known CAFs characterized by high FAP, POSTN, or ACTA2 expression. (Conclusions) We demonstrated that pericryptal fibroblasts and reticular cells in the lamina propria are origins of early-stage CRC CAFs and thus have potential as a diagnostic marker for distinguishing colorectal non-neoplastic from neoplastic lesions.

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.

Incidental findings in the bowel cancer population screening program: other polyps and malignancies - A nationwide study

The introduction of bowel cancer population screening programs has had a profound impact on gastrointestinal pathology. While the focus is mainly on quality assurance of diagnoses relevant for the outcome of these programs (colorectal cancer and its precursors), incidental findings are increasingly diagnosed. The incidence of such findings is largely unknown. Therefore, we investigated the incidence of incidental findings within the national screening program of the Netherlands. From the Dutch nationwide pathology databank (PALGA), we retrieved all histological diagnoses of patients participating in the national bowel cancer screening program from the start in 2014 until 1/1/2021. Descriptive statistics were used. During these 7 years, in total 9407 other polyps and malignancies (262 per 10,000 colonoscopies) were diagnosed. The majority (65%) were classified as inflammatory polyps. The most common malignancies were neuroendocrine tumours (n = 198, 6 per 10,000 colonoscopies); less common were lymphomas (n = 64) and metastases (n = 33). Mesenchymal polyps, such as leiomyomas and lipomas, were relatively common (27 and 16 per 10,000 colonoscopies, respectively), in comparison with neural polyps such as perineuriomas, ganglioneuromas, and neurofibromas (respectively 3, 2, and 1 per 10,000 colonoscopies). This is the largest study into the incidence of nonconventional colorectal polyps and malignancies in a homogeneous cohort of asymptomatic patients. Several of these diagnoses may have consequences for treatment and follow-up, in particular the malignancies and detection of patients with hereditary cancer syndromes.

Rectal Polyposis in Mucosal Prolapse Syndrome

Mucosal prolapse syndrome is also known as solitary rectal ulcer syndrome. It may either presents as an ulcer or polyp, which could mimic other pathological lesions such as juvenile polyp, hyperplastic polyp, adenomatous polyp, polyp related inflammatory bowel disease and adenocarcinoma. It can pose as a diagnostic challenge to both the surgeons and pathologists due to the overlapping gross and histological features. The characteristic histological features of mucosal prolapse syndrome are fibromuscular obliteration of lamina propria and splayed hypertrophic muscularis mucosae. It can occur in a wide range of ages, including children and teenagers. Rectal bleeding is one of the common presenting symptoms. Here, we described two cases of mucosal prolapse syndrome presented as rectal polyposis and provide a discussion on its histological differential diagnosis.

Large prolapse-related lesions of the sigmoid colon

BACKGROUND

Large prolapse-related lesions (LPRL) of the sigmoid colon have been documented histologically but may not be readily recognized endoscopically.

METHODS

Colonic lesions referred for endoscopic mucosal resection (EMR) were enrolled prospectively. Endoscopic features were carefully documented prior to resection. Final diagnosis was made based on established histologic criteria, including vascular congestion, hemosiderin deposition, fibromuscular hyperplasia, and crypt distortion.

RESULTS

Of 134 large ( ≥ 20 mm) sigmoid lesions, 12 (9.0 %) had histologic features consistent with mucosal prolapse. Distinct endoscopic features were: broad-based morphology; vascular pattern obscured by dusky hyperemia; blurred crypts of varying size and shape; and irregular spacing of sparse crypts. Focal histologic dysplasia was identified in 6 of 12 lesions (50.0 %).

CONCLUSIONS

LPRL of the sigmoid colon exhibit a distinct endoscopic profile. Although generally non-neoplastic, dysplasia may be present, warranting consideration of EMR.

Endoscopic Mucosectomy: A Novel Technique for Management of Polypoidal Solitary Rectal Ulcer Syndrome

Solitary rectal ulcer syndrome (SRUS) is an uncommon disorder often challenging to treat. Surgical treatment is associated with suboptimal outcomes and postoperative complications. Argon plasma coagulation helps control rectal bleeding and healing of ulcers, but more extended follow-up data are not available. The macroscopic appearance of SRUS can be polypoid in 17%-25% of cases. Here, we describe a novel endoscopic technique for treating symptomatic patients with polypoidal variant of SRUS after failed medical and endoscopic argon plasma coagulation treatments.

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.

Solitary rectal ulcer syndrome complicating sessile serrated adenoma/polyps: A case report and review of literature

Solitary rectal ulcer syndrome (SRUS) is a rare benign condition, which can mimic many other diseases because of their similarities in clinical, endoscopic and histological features. Sessile serrated adenoma/polyp (SSA/p) is a premalignant lesion in the colon and rectum. The misdiagnosis of SSA/p in SRUS patients has been noted, but the case of SRUS arising secondarily to SSA/p has been rarely reported. We herein report the case of a 59-year-old man who presented with an ulcerative nodular lesion in the rectum, accompanied by the symptoms of blood and mucus in the feces, diarrhea and constipation. Magnetic resonance imagining revealed thickening of the rectal mucosa-submucosa. Histologically, the lesion was characterized by the hyperplastic lamina propria and diffusely serrated crypts. Further immunohistochemical staining showed the loss of HES1 and MLH1 expression in the epithelial cells in the serrated area. The patient with SRUS had histological changes of SSA/p, suggesting a potential of tumor transformation in certain cases. SRUS uncommonly accompanied by serrated lesions should at least be considered by pathologists and clinicians.

Mucosal Prolapse Polyp Mimicking Rectal Malignancy: A Case Report

Mucosal prolapse polyps (MPPs) are rare inflammatory lesions that are part of the mucosal prolapse syndrome. We present the case of a 40-year-old male with history of constipation referred to our institution with suspected rectal malignancy due to hematochezia and a palpable rectal mass. Colonoscopy revealed a 25 mm wide lesion suggestive of subepithelial origin but with marked erythema and erosion in the mucosa. Crypt dilatation and distortion, mixed inflammatory infiltrate and fibrosis were apparent on histological evaluation after bite-on-bite biopsies. Due to the initial suspicion of malignancy, resection was decided after discussion with the patient. However, due to non-elevation partial resection was performed allowing the diagnosis of MPP. Hematochezia ceased after obstipation treatment and endoscopic follow-up showed maintenance of the lesion with the same characteristics except for reduced dimension. MPP may mimic neoplastic lesions and should be considered in the differential diagnosis of rectal masses. History, endoscopy and histological characteristics are all necessary and important in the diagnosis of MPP.

Prolapse-related changes are a confounding factor in misdiagnosis of sessile serrated adenomas in the rectum

The differential diagnosis of rectal serrated polyps is challenging due to its unique anatomic location, the evolving concept of serrated polyps over the past several years, and to histologic changes seen in rectal mucosal prolapse. We reclassified 95 rectal polyps diagnosed originally as "sessile serrated adenoma" (SSA), "serrated polyp," or "hyperplastic polyp (HP) with features of SSA" in a 5-year period based on World Health Organization classification criteria for colorectal serrated polyps. BRAF (V600E) mutation assay was performed to explore its value in the differential diagnosis for serrated polyps. Twenty-six originally diagnosed SSAs were reclassified as SSA (15/26, 57.7%), HP with mucosal prolapse (HP-P; 7/26, 26.9%), and HP (4/26, 15.4%). Fifty-two polyps originally diagnosed "HP with features of SSA" were reclassified as HP-P (24/52, 46.2%), HP (10/52, 19.2%), inflammatory-type polyp (5/52, 9.6%), and serrated polyp unclassifiable (13/52, 25.0%). Thirty-one of the 78 originally diagnosed SSA or HP with features of SSA were reclassified as HP-P, which accounted for 32.6% of the rectal polyps in this study. Mucosal prolapse along with chronic inflammation and tissue embedding artifact were the most common features that led to misdiagnosis in rectal serrated polyps. BRAF mutation was identified in 8 of 11 HP, 4 of 4 SSA, and 8 of 11 unclassifiable serrated polyp of the rectum, and was absent in control tissue. Thus, histopathologic changes suggesting prolapsed rectal mucosa should take precedence over BRAF results.

The clinical, endoscopic and histological spectrum of the solitary rectal ulcer syndrome: a single-center experience of 116 cases

BACKGROUND

Solitary rectal ulcer syndrome (SRUS) is an uncommon although benign defecation disorder. The aim of this study was to evaluate the variable endoscopic manifestations of SRUS and its association with other diseases.

METHODS

All the patients diagnosed with SRUS histologically from January 1990 to February 2011 at The Aga Khan University, Karachi were included in the study. The medical records were reviewed retrospectively to evaluate the clinical spectrum of the patients along with the endoscopic and histological findings.

RESULTS

A total of 116 patients were evaluated. The mean age was 37.4 ± 16.6 (range: 13-80) years, 61 (53%) of the patients were male. Bleeding per rectum was present in 82%, abdominal pain in 49%, constipation in 23% and diarrhea in 22%. Endoscopically, solitary and multiple lesions were present in 79 (68%) and 33 (28%) patients respectively; ulcerative lesions in 90 (78%), polypoidal in 29 (25%), erythematous patches in 3 (2.5%) and petechial spots in one patient. Associated underlying conditions were hemorrhoids in 7 (6%), hyperplastic polyps in 4 (3.5%), adenomatous polyps in 2(2%), history of ulcerative colitis in 3 (2.5%) while adenocarcinoma of colon was observed in two patients. One patient had previous surgery for colonic carcinoma.

CONCLUSION

SRUS may manifest on endoscopy as multiple ulcers, polypoidal growth and erythematous patches and has shown to share clinicopathological features with rectal prolapse, proctitis cystica profunda (PCP) and inflammatory cloacogenic polyp; therefore collectively grouped as mucosal prolapse syndrome. This may be associated with underlying conditions such as polyps, ulcerative colitis, hemorrhoids and malignancy. High index of suspicion is required to diagnose potentially serious disease by repeated endoscopies with biopsies to look for potentially serious underlying conditions associated with SRUS.

[Polyps of the colorectum: non-neoplastic and non-hamartomatous]

Non-neoplastic and non-hamartomatous colorectal polyps or tumor-like lesions comprise a very heterogeneous group of changes in the colorectal mucosa or the colon wall. Mucosal prolapse-associated lesions and inflammatory polyps, which are predominantly associated with chronic inflammatory bowel disease, are the most prominent examples for polypoid lesions difficult to distinguish from neoplastic lesions such as adenomas, hyperplastic/serrated polyps/adenomas and invasive carcinomas. The considerably less frequent tumor-like lesions like heterotopias, endometriosis, amyloid tumors and pseudolipomatous changes are histologically often well defined and should be considered in the differential diagnosis of colorectal lesions. The etiology, endoscopic and histological appearance of these entities and their most important differential diagnoses are discussed.

Detection of desmoplastic reaction in biopsy specimens is useful for predicting the depth of invasion of early colorectal cancer: a Japanese collaborative study

BACKGROUND

We have previously demonstrated a relationship between the depth of submucosal invasion (SM depth) and the frequency of lymph node metastasis in resected submucosal invasive colorectal cancers (SICRCs). Here, we assessed the desmoplastic reaction (DR) in pretreatment biopsy specimens of SICRC to predict the SM depth.

METHODS

A total of 359 patients with SICRCs, who had undergone surgical or endoscopic mucosal resection, were enrolled. The SM depth of the SICRC lesions was evaluated according to the procedure established by the Japanese Society for Cancer of the Colon and Rectum, and the patients' corresponding pretreatment biopsy specimens were examined histologically to evaluate the prevalence of DR.

RESULTS

For pedunculated SICRCs, the prevalence of DR in pretreatment biopsy specimens was significantly higher in moderately differentiated than in well-differentiated adenocarcinomas, but was not significantly related to SM depth. For nonpedunculated SICRCs, the prevalence of DR in pretreatment biopsy specimens was significantly related to histological type, tumor size, and SM depth. When non-pedunculated SICRCs were further divided using a specific cutoff value of 1000 μm for SM depth, the DR positivity rate in pretreatment biopsy specimens was significantly higher in SICRCs with an SM depth of ≥1000 μm (termed "SM massive CRCs") than in cases where the SM depth was <1000 μm (termed "SM slight CRCs").

CONCLUSIONS

Detection of DR in pretreatment biopsy specimens is useful for the prediction of SM depth in nonpedunculated SICRCs, and may be useful for the selection of such cases that would be treatable by endoscopic mucosal resection and endoscopic submucosal dissection (EMR/ESD).