Histomorphologic and Molecular Features of Pouch and Peripouch Adenocarcinoma: A Comparison With Ulcerative Colitis-associated Adenocarcinoma

Histopathological Evaluation of Pouch Neoplasia in IBD and Familial Adenomatous Polyposis

BACKGROUND

IPAA is often required for patients with ulcerative colitis or familial adenomatous polyposis after colectomy. This procedure reduces but does not completely eliminate the risk of neoplasia.

OBJECTIVE

This study focuses on the histopathology of neoplasia in the ileal pouch, rectal cuff, and anal transition zone.

DATA SOURCES

We performed a MEDLINE search for English-language studies published between 1981 and 2022 using the PubMed search engine. The terms "ileal pouch-anal anastomosis," "pouchitis," "pouch dysplasia," "pouch lymphoma," "pouch squamous cell carcinoma," "pouch adenocarcinoma," "pouch neoplasia," "dysplasia of rectal cuff," and "colitis-associated dysplasia" were used.

STUDY SELECTION

Human studies of neoplasia occurring in the pouch and para-pouch were selected, and the full text was reviewed. Comparisons were made within and across studies, with key concepts selected for inclusion in this article.

CONCLUSIONS

Neoplasia in the pouch is a rare complication in patients with IPAA. Annual endoscopic surveillance is recommended for familial adenomatous polyposis patients and ulcerative colitis patients with a history of prior dysplasia or carcinoma. In familial adenomatous polyposis, dysplastic polyps of the pouch are visible and readily amenable to endoscopic removal; however, glandular dysplasia in the setting of ulcerative colitis may be invisible on endoscopy. Therefore, random biopsies and adequate tissue sampling of the pouch and rectal cuff are recommended in this setting. The histological diagnosis of IBD-associated dysplasia can be challenging and should be confirmed by at least 1 expert GI pathologist. See video from the symposium.

Histopathology of Pouch and Para-Pouch Inflammatory and Neoplastic Disorders

BACKGROUND

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is used to treat patients with ulcerative colitis or familial adenomatous polyposis who need colectomy. While this procedure substantially improves patient's quality of life and reduces cancer risk, it is associated with a variety of sequelae' including surgical complications, inflammatory disorders, and neoplasia. Pouchitis, cuffitis, and Crohn's disease of the pouch are the most common inflammatory disorders of the pouch and para-pouch.

OBJECTIVE

This study aimed to elaborate on the histopathology of common inflammatory and neoplastic disorders of the pouch and para-pouch.

DATA SOURCES

A Medline search for English language studies published between 1981 and 2021 using the PubMed search engine. The terms "ileal pouch-anal anastomosis," "pouchitis," "pouchitis activity score," "secondary pouchitis," "Crohn's disease of the pouch," "Crohn's-like conditions of the pouch," "pre-pouch ileitis," "cuffitis," "pouch adenocarcinoma," and "pouch neoplasia" were used.

STUDY SELECTION

The published human studies that reported histopathology of common inflammatory and neoplastic disorders of the ileal pouch were selected and reviewed.

CONCLUSIONS

Histologic examination plays an essential role in confirming inflammation in pouchitis, identifying etiology and clues for secondary pouchitis, and diagnosing neoplasia. A standardized, simple, and reproducible histologic grading system for pouchitis is needed. Pouch and para-pouch glandular dysplasia diagnosis is challenging and should always be reviewed by at least one gastrointestinal pathologist.

Management of pouch neoplasia: consensus guidelines from the International Ileal Pouch Consortium

Surveillance pouchoscopy is recommended for patients with restorative proctocolectomy with ileal pouch-anal anastomosis in ulcerative colitis or familial adenomatous polyposis, with the surveillance interval depending on the risk of neoplasia. Neoplasia in patients with ileal pouches mainly have a glandular source and less often are of squamous cell origin. Various grades of neoplasia can occur in the prepouch ileum, pouch body, rectal cuff, anal transition zone, anus, or perianal skin. The main treatment modalities are endoscopic polypectomy, endoscopic ablation, endoscopic mucosal resection, endoscopic submucosal dissection, surgical local excision, surgical circumferential resection and re-anastomosis, and pouch excision. The choice of the treatment modality is determined by the grade, location, size, and features of neoplastic lesions, along with patients' risk of neoplasia and comorbidities, and local endoscopic and surgical expertise.

Incidence and Risk Factors of Cancer in the Anal Transitional Zone and Ileal Pouch following Surgery for Ulcerative Colitis and Familial Adenomatous Polyposis

Proctocolectomy with ileal pouch-anal anastomosis is the intervention of choice for ulcerative colitis and familial adenomatous polyposis requiring surgery. One of the long-term complications is pouch cancer, having a poor prognosis. The risk of high-grade dysplasia and cancer in the anal transitional zone and ileal pouch after 20 years is estimated to be 2 to 4.5% and 3 to 10% in ulcerative colitis and familial polyposis, respectively. The risk factors for ulcerative colitis are the presence of pre-operative dysplasia or cancer, disease duration > 10 years and severe villous atrophy. For familial polyposis, the risk factors are the number of pre-operative polyps > 1000, surgery with stapled anastomosis and the duration of follow-up. In the case of ulcerative colitis, a pouchoscopy should be performed annually if one of the following is present: dysplasia and cancer at surgery, primary sclerosing cholangitis, villous atrophy and active pouchitis (every 5 years without any of these factors). In the case of familial polyposis, endoscopy is recommended every year including chromoendoscopy. Even if anal transitional zone and ileal pouch cancers seldom occur following proctectomy for ulcerative colitis and familial adenomatous polyposis, the high mortality rate associated with this complication warrants endoscopic monitoring.

Diagnosis and classification of ileal pouch disorders: consensus guidelines from the International Ileal Pouch Consortium

Restorative proctocolectomy with ileal pouch-anal anastomosis is an option for most patients with ulcerative colitis or familial adenomatous polyposis who require colectomy. Although the construction of an ileal pouch substantially improves patients' health-related quality of life, the surgery is, directly or indirectly, associated with various structural, inflammatory, and functional adverse sequelae. Furthermore, the surgical procedure does not completely abolish the risk for neoplasia. Patients with ileal pouches often present with extraintestinal, systemic inflammatory conditions. The International Ileal Pouch Consortium was established to create this consensus document on the diagnosis and classification of ileal pouch disorders using available evidence and the panellists' expertise. In a given individual, the condition of the pouch can change over time. Therefore, close monitoring of the activity and progression of the disease is essential to make accurate modifications in the diagnosis and classification in a timely manner.

Controversies in Pouch Surveillance for Patients with Inflammatory Bowel Disease

CASE 1

Following 2 years of rectal blood loss, a 31-year-old male was diagnosed with ulcerative pancolitis in 1978. Initial treatment consisted of both topical and systemic 5-aminosalicylic acids [5-ASAs], and remission was achieved. In both 1984 and 1986 he was hospitalised due to exacerbations necessitating treatment with intravenous corticosteroids. The following years went well, without disease activity, under treatment with 5-ASA. In 1997, at the age of 50 years, a surveillance colonoscopy showed a stenotic process with a macroscopic irregularity in the sigmoid region. Histology revealed at least high-grade dysplasia [HGD] and signs of an invasive growth pattern which could indicate colorectal cancer [CRC]. The patient underwent restorative proctocolectomy with ileal pouch-anal anastomosis [IPAA]. Histology of the resection specimen confirmed active inflammation in the colon and rectum and a carcinoma in situ was identified in the sigmoid colon without invasive growth. This patient did not have significant comorbidities-for example primary sclerosing cholangitis [PSC]-and the CRC family history was negative. What pouch surveillance strategy should be recommended?

CASE 2

A 34-year-old man presented at our inflammatory bowel disease [IBD] centre with ulcerative proctitis. Ten years later, after an initially mild disease course, his disease progressed to a pancolitis. An 11-year period with multiple exacerbations [on average every 2 year, including hospitalisation] followed and treatment consisted of topical and systemic 5-ASAs with intermittent corticosteroids. In 1998, at the age of 65 years, a two-stage restorative proctocolectomy with IPAA was performed due to disease activity refractory to systemic corticosteroids. The colectomy specimen confirmed the diagnosis of ulcerative pancolitis without evidence for colorectal dysplasia or carcinoma. Other than steroid-induced diabetes mellitus, this patient had no comorbidities. His father died from CRC at unknown age. What pouch surveillance strategy should be recommended?

Common Inflammatory Disorders and Neoplasia of the Ileal Pouch: A Review of Histopathology

Ileal pouch-anal anastomosis (IPAA) is the standard restorative procedure after proctocolectomy in patients with ulcerative colitis (UC) who require colectomy. The ileal pouch is susceptible to a variety of insults including mechanical injury, ischemia, fecal stasis, and infectious agents. In addition, the development of recurrent and idiopathic inflammatory bowel disease and neoplasia may occur in the ileal pouch. Although clinical, endoscopic, and radiographic examination can diagnose many ileal pouch diseases, histologic examination plays an essential role in diagnosis and management, particularly in cases with antibiotic refractory chronic pouchitis and pouch neoplasia.

Disease course and management strategy of pouch neoplasia in patients with underlying inflammatory bowel diseases

BACKGROUND

To evaluate the disease course and management strategy for pouch neoplasia.

METHODS

Patients undergoing ileal pouch surgery for underlying ulcerative colitis who developed low-grade dysplasia (LGD), high-grade dysplasia, or adenocarcinoma in the pouch were identified.

RESULTS

All eligible 44 patients were evaluated. Of the 22 patients with initial diagnosis of pouch LGD, 6 (27.3%) had persistence or progression after a median follow-up of 9.5 (4.1-17.6) years. Family history of colorectal cancer was shown to be a risk factor associated with persistence or progression of LGD (P = 0.03). Of the 12 patients with pouch high-grade dysplasia, 5 (41.7%) had a history of (n = 2, 16.7%) or synchronous (n = 4, 33.3%) pouch LGD. Pouch high-grade dysplasia either persisted or progressed in 3 patients (25.0%) after the initial management, during a median time interval of 5.4 (2.2-9.2) years. Of the 14 patients with pouch adenocarcinoma, 12 (85.7%) had a history of (n = 2, 14.3%) or synchronous dysplasia (n = 12, 85.7%). After a median follow-up of 2.1 (0.6-5.2) years, 6 patients with pouch cancer (42.9%) died. Comparison of patients with a final diagnosis of pouch adenocarcinoma (14, 32.6%), and those with dysplasia (29, 67.4%) showed that patients with adenocarcinoma were older (P = 0.04) and had a longer duration from IBD diagnosis or pouch construction to the detection of pouch neoplasia (P = 0.007 and P = 0.0013).

CONCLUSIONS

The risk for progression of pouch dysplasia can be stratified. The presence of family history of colorectal cancer seemed to increase the risk for persistence or progression for patients with pouch LGD. The prognosis for pouch adenocarcinoma was poor.

Systematic review of cuff and pouch cancer in patients with ileal pelvic pouch for ulcerative colitis

BACKGROUND

Ileal pouch-anal anastomosis (IPAA) is the procedure of choice for refractory or complicated ulcerative colitis (UC). Since 1990, pouch-related adenocarcinomas have been described. The aim of this study was to review the literature to evaluate the burden of this complication, seeking for risk factors, prevention, and ideal management.

METHODS

We performed a systematic review of the literature to identify all described pouch-related adenocarcinoma in patients operated on with IPAA for UC. Studies were thoroughly evaluated to select authentic de novo pouch carcinomas. Some authors were contacted for additional information. Data of patients were pooled. Meta-analyses of suitable studies were attempted to identify risk factors.

RESULTS

Thirty-four articles reported on 49 patients (2:1, male:female) who developed unequivocal pouch-related adenocarcinoma, 14 (28.6%) and 33 (67.3%) arising from the pouch and anorectal mucosa, respectively. Origin was not reported in 2 (4%). Pooled cumulative incidence of pouch-related adenocarcinoma was 0.33% (95% confidence interval [CI], 0.31-0.34) 50 years after the diagnosis and 0.35% (95% CI, 0.34-0.36) 20 years after IPAA. Primary pouch cancer incidence was below 0.02% 20 years after IPAA. Neoplasia on colectomy specimen was the strongest risk factor (odds ratio, 8.8; 95% CI, 4.61-16.80). Mucosectomy did not abolish the risk of subsequent cancer but avoiding it increased 8 times the risk of cancer arising from the residual anorectal mucosa (odds ratio, 8; 95% CI, 1.3-48.7; P = 0.02). Surveillance is currently performed yearly starting 10 years since diagnosis, but cancers escaping this pathway are reported. In patients receiving mucosectomy, a 5-year delay for surveillance could be proposed.

CONCLUSIONS

Pouch-related adenocarcinomas are rare. Diagnosis of Crohn's disease in the long term may further decrease the rates in UC. Presumed evolution from dysplasia might offer a time window for cancer prevention. Abdominoperineal excision should be recommended for pouch-related adenocarcinomas.

Novel specific microRNA biomarkers in idiopathic inflammatory bowel disease unrelated to disease activity

The diagnosis of idiopathic inflammatory bowel disease can be challenging. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate protein synthesis through post-transcriptional suppression. This study is to identify new miRNA markers in inflammatory bowel disease, and to examine whether miRNA biomarkers might assist in the diagnosis of inflammatory bowel disease. Illumina small RNA sequencing was performed on non-dysplastic fresh-frozen colonic mucosa samples of the distalmost colectomy tissue from 19 patients with inflammatory bowel disease (10 ulcerative colitis and 9 Crohn disease) and 18 patients with diverticular disease serving as controls. To determine differentially expressed miRNAs, the USeq software package identified 44 miRNAs with altered expression (fold change ≥ 2 and false discovery rate ≤ 0.10) compared with the controls. Among them, a panel of nine miRNAs was aberrantly expressed in both ulcerative colitis and Crohn disease. Validation assays performed using quantitative reverse transcription PCR (qRT-PCR) on additional frozen tissue from ulcerative colitis, Crohn disease, and control groups confirmed specific differential expression in inflammatory bowel disease for miR-31, miR-206, miR-424, and miR-146a (P<0.05). The expression of these four miRNAs was further evaluated on formalin-fixed, paraffin-embedded tissue of the distalmost colectomy mucosa from cohorts of diverticular disease controls (n=29), ulcerative colitis (n=36), Crohn disease (n=26), and the other diseases mimicking inflammatory bowel disease including infectious colitis (n=12) and chronic ischemic colitis (n=19), again confirming increased expression specific to inflammatory bowel disease (P<0.05). In summary, we demonstrate that miR-31, miR-206, miR-424, and miR-146a are novel specific biomarkers of inflammatory bowel disease. Furthermore, miR-31 is universally expressed in both ulcerative colitis and Crohn disease not only in fresh-frozen but also in formalin-fixed, paraffin-embedded tissues.

Colorectal dysplasia in inflammatory bowel disease: a clinicopathologic perspective

Surveillance for neoplasia in colitis is the most challenging diagnostic colonoscopic procedure. The detection and treatment of colorectal dysplasia in inflammatory bowel disease remain problematic to the point that unsuspected colorectal cancers (CRCs) are still identified. Excellent bowel preparation and use of high-resolution colonoscopes with chromoendoscopy facilitate the detection and characterization of subtle neoplasia. This approach is superior to taking random biopsy specimens and should be the standard of care for surveillance but requires adequate training. Suspicious lesions should be assessed carefully and described using objective terminology. The terms dysplasia-associated lesions/masses and flat dysplasia are best avoided because they may be open to misinterpretation. Most suspicious lesions detected during surveillance can be removed endoscopically, precluding the need for surgery. Nevertheless, endotherapy in colitis can be difficult as a result of underlying inflammation and scarring. Lesions that are not endoscopically resectable need to be removed surgically, although the possibility that some lesions might be amenable to local resection (including lymphadenectomy) rather than subtotal colectomy may need to be re-evaluated. Despite surveillance programs, patients still present clinically with CRC. This may occur because lesions are missed (possibly because of the failure to use optimal techniques), lesions are not adequately removed, patients fail to return for colonoscopy, or CRCs arise rapidly in mucosa that is minimally dysplastic and the CRCs are not recognized as being potentially invasive even on biopsy. Future advances in, for example, stool DNA assays, use of confocal endomicroscopy, or use of endoscopic ultrasound, may help in the identification of high-risk patients and the assessment of dysplastic lesions.

Diagnostic utility of TP53 and cytokeratin 7 immunohistochemistry in idiopathic inflammatory bowel disease-associated neoplasia

Long-standing inflammatory bowel disease is associated with increased risk of developing colorectal adenocarcinoma. Significant intra- and inter-observers' variability exists in histologic interpretation of dysplasia in surveillance biopsies. In this study, we evaluated the utility of a panel of immunohistochemical markers in diagnosing inflammatory bowel disease-associated neoplasia. We reviewed 39 colectomy specimens with inflammatory bowel disease-associated neoplasia. In these 39 cases, we identified 172 foci of interest (5 normal, 58 negative for dysplasia, 15 indefinite for dysplasia, 59 low-grade dysplasia, 18 high-grade dysplasia, and 17 invasive adenocarcinoma). They were subjected to immunohistochemistry for TP53 and CK7. Logistic regression was used to evaluate their association with the presence of dysplasia. Receiver operating characteristic curves were used to determine the optimal cutoffs and assess the diagnostic performance of TP53 and CK7. Both TP53 nuclear staining and CK7 immunoreactivity gradually increased in the progression of inflammatory bowel disease-associated neoplasia (P<0.0001). CK7 immunoreactivity increased along with the increase of inflammation severity (P=0.0002) as well as reactive changes (P=0.04) in the colonic mucosa. But TP53 nuclear staining was independent of either feature. When both TP53>8% and CK7>30% as identified from logistic regression and receiver operating characteristic curves were used to diagnose dysplasia, the specificity achieved as high as 95%. When either TP53>8% or CK7>30% was used to diagnose dysplasia, the sensitivity achieved was 82%. Our results suggested that a combination of CK7 and TP53 immunohistochemistry may be helpful in diagnosing inflammatory bowel disease-associated dysplasia in difficult cases.

Prior colorectal neoplasia is associated with increased risk of ileoanal pouch neoplasia in patients with inflammatory bowel disease

BACKGROUND & AIMS

Although restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) substantially reduces the risk of colorectal cancer in patients with inflammatory bowel disease (IBD), subsequent pouch neoplasia can develop. There are few data on the incidence of and risk factors for neoplasia, so there is no consensus on the need for pouch surveillance. We aimed to determine the cumulative incidence of pouch neoplasia in patients with IBD and identify risk factors for developing pouch neoplasia.

METHODS

We searched the Dutch Pathology Registry (PALGA) to identify all patients with IBD and IPAA in The Netherlands from January 1991 to May 2012. We calculated the cumulative incidence of pouch neoplasia and performed a case-control study to identify risk factors. Demographic and clinical variables were analyzed with univariable and multivariable Cox regression analyses.

RESULTS

We identified 1200 patients with IBD and IPAA; 25 (1.83%) developed pouch neoplasia, including 16 adenocarcinomas. Respective cumulative incidences at 5, 10, 15, and 20 years were 1.0%, 2.0%, 3.7%, and 6.9% for pouch neoplasia and 0.6%, 1.4%, 2.1%, and 3.3% for pouch carcinoma. A history of colorectal neoplasia was the only risk factor associated with pouch neoplasia. Hazard ratios were 3.76 (95% confidence interval, 1.39-10.19) for prior dysplasia and 24.69 (95% confidence interval, 9.61-63.42) for prior carcinoma.

CONCLUSIONS

The incidence of pouch neoplasia in patients with IBD without a history of colorectal neoplasia is relatively low. Prior dysplasia or colon cancer is associated with an approximate 4- and 25-fold increase in risk, respectively, of developing pouch neoplasia.

Layered signaling regulatory networks analysis of gene expression involved in malignant tumorigenesis of non-resolving ulcerative colitis via integration of cross-study microarray profiles

Background

Ulcerative colitis (UC) was the most frequently diagnosed inflammatory bowel disease (IBD) and closely linked to colorectal carcinogenesis. By far, the underlying mechanisms associated with the disease are still unclear. With the increasing accumulation of microarray gene expression profiles, it is profitable to gain a systematic perspective based on gene regulatory networks to better elucidate the roles of genes associated with disorders. However, a major challenge for microarray data analysis is the integration of multiple-studies generated by different groups.

Methodology/Principal Findings

In this study, firstly, we modeled a signaling regulatory network associated with colorectal cancer (CRC) initiation via integration of cross-study microarray expression data sets using Empirical Bayes (EB) algorithm. Secondly, a manually curated human cancer signaling map was established via comprehensive retrieval of the publicly available repositories. Finally, the co-differently-expressed genes were manually curated to portray the layered signaling regulatory networks.

Results

Overall, the remodeled signaling regulatory networks were separated into four major layers including extracellular, membrane, cytoplasm and nucleus, which led to the identification of five core biological processes and four signaling pathways associated with colorectal carcinogenesis. As a result, our biological interpretation highlighted the importance of EGF/EGFR signaling pathway, EPO signaling pathway, T cell signal transduction and members of the BCR signaling pathway, which were responsible for the malignant transition of CRC from the benign UC to the aggressive one.

Conclusions

The present study illustrated a standardized normalization approach for cross-study microarray expression data sets. Our model for signaling networks construction was based on the experimentally-supported interaction and microarray co-expression modeling. Pathway-based signaling regulatory networks analysis sketched a directive insight into colorectal carcinogenesis, which was of significant importance to monitor disease progression and improve therapeutic interventions.