Hyperplastic polyposis of the large bowel. Three cases and a review of the literature

Gastrointestinal polyposis with associated cutaneous manifestations

Cutaneous findings are commonly associated with underlying gastrointestinal disorders and, in many instances, may be the first manifestation. Many such syndromes have incomplete penetrance and variable expressivity, making them difficult to recognise. Skin manifestations may be an easily recognised feature of the underlying disorder. Most of these syndromes are hereditary but not all are associated with malignancies; either benign or premalignant extraintestinal lesions can be the initial manifestation. Some involve a single organ system, while others involve multiple organs of the gastrointestinal tract. In this review, we have focused on Lynch syndrome (hereditary nonpolyposis colon cancer and Muir-Torre syndrome), familial adenomatous polyposis, the hamartomatous polyposis syndromes that include Peutz-Jeghers syndrome and the PTEN hamartoma syndromes, which include Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome and, lastly, Cronkhite-Canada syndrome, which is not heritable. Some of these are associated with colorectal cancer, of which 15% are heritable. The majority are inherited in an autosomal dominant fashion. These syndromes are uncommon. However, because of the strong association with the cutaneous findings, early detection and screening may be possible and are key to decreasing the morbidity and mortality associated with them, for both the patient and family members. The clinical findings, epidemiological findings, underlying genetic alterations and pathological findings are reviewed.

Long-Term Incidence of Advanced Colorectal Neoplasia in Patients with Serrated Polyposis Syndrome: Experience in a Single Academic Centre

Simple Summary

Serrated polyposis syndrome is characterized by the development of large and/or multiple serrated polyps throughout the colorectum and is associated with an increased risk of colorectal cancer (CRC). Even though CRC incidence is low under adequate endoscopic follow-up, a substantial risk of advanced neoplasia (AN) has been described. Nevertheless, very few studies have focused on long-term surveillance. The main aim of this study was to evaluate the incidence of AN in a single-centre cohort followed over 10 years. Within endoscopic surveillance we did not find any CRC and we observed that five-year cumulative incidences of AN were much lower than in other studies. However, a significant reduction of these incidences during follow-up was not proven. Individuals at higher risk of AN were those who fulfilled both 2010 WHO criteria I and III. Our results suggest that at least patients at lower risk might benefit from the extension of surveillance intervals.

Abstract

Serrated polyposis syndrome (SPS) implies a slightly elevated risk of colorectal cancer (CRC) during endoscopic follow-up, but its natural course is still not well known. The main objective of this study was to describe the long-term risk of developing advanced neoplasia (AN) in these patients. Until October 2020, individuals who fulfilled 2010 WHO criteria I and/or III for SPS were retrospectively recruited. We selected those under endoscopic surveillance after resection of all lesions >3 mm in a high-quality colonoscopy. We excluded patients with total colectomy at diagnosis and those with any interval between colonoscopies >3.5 years. We defined AN as advanced serrated polyp (≥10 mm and/or with dysplasia), advanced adenoma, or CRC. In 109 patients, 342 colonoscopies were performed (median = 3, median interval = 1.8 years) during a median follow-up after colonic clearance of 5.0 years. Five-year cumulative incidences of AN were 21.6% globally, and 5.6%, 10.8%, and 50.8% in patients who fulfilled criterion I, III, and both, respectively (p < 0.001). No CRC was diagnosed and only 1 (0.9%) patient underwent surgery. In conclusion, cumulative incidences of AN could be lower than previously described, at least in patients who fulfil the 2010 WHO criterion III alone. Therefore, low-risk individuals might benefit from less stringent surveillance.

Management of Serrated Polyps of the Colon

PURPOSE OF REVIEW

The purpose of this review is to summarize the management of serrated colorectal polyps (SPs), with a particular focus on the most common premalignant SP, sessile serrated adenoma or polyp (SSA/P). These lesions present a challenge for endoscopists with respect to detection and resection, and are also susceptible to pathologic misdiagnosis.

RECENT FINDINGS

Patients with SSA/Ps are at an increased risk of future colorectal neoplasia, including advanced polyps and cancer. Reasonable benchmarks for SP detection rates are 5-7% for SSA/Ps and 10-12% for proximal SPs. Certain endoscopic techniques such as chromoendoscopy, narrow band imaging, water immersion, and wide-angle viewing may improve SSA/P detection. Emerging endoscopic techniques such as underwater polypectomy, suction pseudopolyp technique, and piecemeal cold snare polypectomy are helpful tools for the endoscopist's armamentarium for removing SSA/Ps. Proper orientation of SSA/P specimens can improve the accuracy of pathology readings. Patients with confirmed SSA/Ps and proximal HPs should undergo surveillance at intervals similar to what is recommended for patients with conventional adenomas. Patients with SSA/Ps may also be able to lower their risk of future polyps by targeting modifiable risk factors including tobacco and alcohol use and high-fat diets. NSAIDs and aspirin appear to be protective agents. SPs and SSA/Ps in particular are important colorectal cancer precursors that merit special attention to ensure adequate detection, resection, and surveillance.

Endoscopic diagnosis of colorectal serrated lesions: Current status and future perspectives based on the results of a questionnaire survey

Serrated lesions, especially sessile serrated adenoma/polyps (SSA/P) are considered one of the most important precursors of colorectal cancers. However, it is still difficult to endoscopically differentiate SSA/P from hyperplastic polyps. In the present review, we mainly focus on the current status and future perspectives of endoscopic diagnosis of colorectal serrated lesions based on the results of a questionnaire survey and report from the Endoscopic Forum Japan (EFJ) 2015 held in Tokyo in August 2015. The proposed diagnostic strategy recommended for colorectal serrated lesions is as follows. (i) For detection, use of an updated image-enhanced endoscopy system including autofluorescence imaging (AFI) and narrow-band imaging (NBI) may be promising. (ii) For differential diagnosis (hyperplastic polyp or SSA/P) of diminutive, small and large serrated lesions, NBI with magnification and magnifying chromoendoscopy using both indigocarmine and crystal violet should be applied, respectively. (iii) For differential diagnosis of SSA/P (with or without cytological dysplasia), magnifying chromoendoscopy, endocytoscopy and updated AFI system modalities might be promising.

Cutaneous manifestation of gastrointestinal disease

The gastrointestinal (GI) and cutaneous systems are closely linked in origin. Skin manifestations are frequently seen as a part of different GI syndromes. Gastroenterologists play an important role in recognizing the symptoms, patient workup and arriving at appropriate diagnoses, often in consultation with dermatologists. This review discusses the diseases with both cutaneous and intestinal involvement. Hereditary polyposis GI cancers, hereditary nonpolyposis colorectal cancers (CRCs), hamartomatous disorders, and inflammatory bowel disease (IBD) are reviewed with emphasis on the genetic basis, diagnostic, histologic findings, screening modalities, and therapeutic options.

Prevalence of serrated polyposis syndrome and its association with synchronous advanced adenoma and lifestyle

We assessed the clinicopathological characteristics of patients with serrated polyposis syndrome (SPS) and the incidence of advanced adenoma/colorectal cancer (CRC). We prospectively enrolled 249 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital over a 6-month period. All the polyps were diagnosed using magnification colonoscopy and resection/biopsy. The enrolled patients were divided into two groups, i) those with ≥5 histologically diagnosed hyperplastic polyps (HPs) proximal to the sigmoid colon, with at least 2 polyps >10 mm in diameter and ii) those with ≥20 HPs distributed throughout the colon. The clinical characteristics of the two groups were compared, including lifestyle, family history of CRC and colonoscopic findings. HPs were identified in 228 patients, of whom 21 (8.4%) had SPS. All 21 patients had ≥20 HPs distributed throughout the colon, with none having >2 HPs ≥1 cm in diameter in the right colon. Synchronous advanced adenoma/CRC was diagnosed in 76/249 (30.5%) patients. The prevalence of advanced adenoma/CRC was higher among patients with compared to those without SPS (P=0.075). SPS was also associated with older age and higher body mass index (BMI). Our results suggested that older age and higher BMI are independent risk factors for SPS. Advanced adenoma/CRC tended to occur more frequently among patients with compared to those without SPS, although the difference was not statistically significant.

Serrated polyps detected during screening colonoscopies

AIM OF THE STUDY

It is estimated that between 15% and 35% of sporadic colorectal cancers (CRC) developing from adenomas come from serrated polyps. Currently, the most effective method used to prevent CRC is the removal of adenomas, including serrated polyps, during colonoscopy. The aim of this paper is to analyze the changes characterized as serrated polyps and detected during screening colonoscopies performed as part of the Screening Program for Early Colorectal Cancer Detection (SPED).

MATERIAL AND METHODS

In our center, as part of the nationwide SPED between 2000 and 2009, 1,442 screening colonoscopies were performed.

RESULTS

Serrated polyps were found in 11.9% of all patients and in 45.8% of patients who had polyps removed by endoscopy. In screening colonoscopy of the large intestine, the following polyps were found most frequently: hyperplastic, < 1 cm, without a stalk, multiple, located in the distal part of the large intestine, in men and in patients with a first-degree relative with a history of abdominal cancer. Detecting and removing polyps was facilitated by the fact that the cecum was intubated and the bowel preparation had been performed either very well or well. The detection rate of serrated polyps was not influenced by patients' place of residence or their age.

CONCLUSIONS

Serrated polyps constitute a frequent, and very frequent among removed polyps, abnormality detected during screening colonoscopy.

Serrated polyposis: an enigmatic model of colorectal cancer predisposition

Serrated polyposis has only recently been accepted as a condition which carries an increased personal and familial risk of colorectal cancer. Described over four decades ago, it remains one of the most underrecognized and poorly understood of all the intestinal polyposes. With a variety of phenotypic presentations, it is likely that serrated polyposis represents a group of diseases rather than a single entity. Further, neoplastic progression in serrated polyposis may be associated with premature aging in the normal mucosa, typified by widespread gene promoter hypermethylation. From this epigenetically altered field, arise diverse polyps and cancers which show a range of molecular features. Despite a high serrated polyp count, only one-third of colorectal cancers demonstrate a BRAF V600E mutation, the molecular hallmark of the canonical serrated pathway, suggesting that though multiple serrated polyps act as a marker of an abnormal mucosa, the majority of CRC in these patients arise within lesions other than BRAF-mutated serrated polyps.

The clinical significance of serrated polyps

Colorectal cancer (CRC) is a heterogeneous disorder than arises via multiple distinct pathways, such as the serrated pathway, in which serrated polyps (including variants of hyperplastic polyps) are the precursor lesions. Approximately 15-20% of all CRCs arise via the serrated pathway, and these serrated carcinomas are clinically, morphologically, and molecularly distinct from conventional CRCs. The prevention of serrated carcinomas represents an important clinical challenge. Gastroenterologists need to recognize and remove potential precursor lesions and implement a post-polypectomy surveillance program when appropriate. This article focuses on the characteristics and significance of clinically relevant serrated polyps and addresses implications for CRC prevention practices.

Serrated adenoma: a distinct form of non-polypoid colorectal neoplasia?

Until recently, 2 major forms of colorectal polyp were recognized: the adenoma and the hyperplastic polyp. Adenomas were known to represent a precursor to colorectal cancer, whereas hyperplastic polyps were viewed as nonneoplastic, having no potential for progression to malignancy. We now recognize, however, that the lesions diagnosed as hyperplastic polyps in the past represent a heterogeneous group of polyps, some of which truly are hyperplastic, and others that truly have a significant risk for transformation to colorectal cancer. These polyps have a characteristic serrated architecture, and include not only hyperplastic polyps but also the recently recognized serrated adenomas. Serrated adenomas occur in 2 forms: the traditional serrated adenoma, which is usually a polypoid lesion endoscopically, and the sessile serrated adenoma, a flat or slightly raised, usually right-sided lesion. Serrated adenomas of both types show characteristic molecular alterations not commonly seen in traditional colorectal adenomas, and probably progress to colorectal cancer by means of a different pathway, the so-called serrated neoplasia pathway. The morphologic features of serrated colorectal lesions, the molecular alterations that characterize them, and their role in colorectal cancer development are discussed.

Serrated polyps and colorectal cancer: new pathway to malignancy

Until recently, two major forms of colorectal epithelial polyp were recognized: the adenoma and the hyperplastic polyp. Adenomas were perceived to represent the precursor to colorectal cancer, whereas hyperplastic polyps were viewed as innocuous lesions with no potential for progression to malignancy. We now recognize, however, that the lesions formerly classified as hyperplastic actually represent a heterogeneous group of polyps, some of which have a significant risk for neoplastic transformation. These serrated polyps include not only hyperplastic polyps but also traditional serrated adenomas and sessile serrated adenomas. These polyps demonstrate characteristic molecular alterations not commonly seen in colorectal adenomas, and they probably progress to colorectal cancer by means of a new pathway: the serrated neoplasia pathway. The morphologic features of serrated colorectal lesions, the molecular alterations that characterize them, and their role in colorectal cancer development are discussed herein.

Colorectal polyposes: from phenotype to diagnosis

The colorectal polyposes are uncommon and frequently present diagnostic difficulties. Although the final diagnostic arbiter is the demonstration of a germline mutation, this may not always be demonstrable, and some forms of colorectal polyposis have no known genetic basis. Therefore, an accurate description of the phenotype by the pathologist is central to the establishment of a working diagnosis. This can direct the search for the underlying genetic cause (if any) and is also essential for establishing the magnitude of risk of colorectal malignancy for the patient and the patient's relatives. The pathologist may be provided with only a small and selected sample of endoscopically resected polyps or with prodigious numbers of polyps (too many to sample) when receiving a surgical specimen. Each type of polyposis presents its own particular diagnostic problems that may relate to polyp numbers, gross recognition of small or flat polyps, incomplete development of the full phenotype at the stage of investigation, and the histological classification of unusual or mixed polyps. The aim of this review is to highlight the principles and pitfalls in achieving a comprehensive description of the various types of colorectal polyposis, including classical FAP, attenuated FAP, MUTYH- (formerly MYH-) associated polyposis (MAP), other presentations of multiple adenomas, Peutz-Jeghers syndrome (P-JS), juvenile polyposis syndrome (JPS), Cowden syndrome (CS), hereditary mixed polyposis syndrome (HMPS), and hyperplastic polyposis syndrome (HPS).

Gastrointestinal polyposes: clinical, pathological and molecular features

This article focuses mainly on noninflammatory epithelial polyposes, particularly the diagnostically important morphological and molecular features of the more recently recognized and/or more poorly understood conditions. One of the most important, but often neglected, of these is hyperplastic polyposis.

Molecular classification and genetic pathways in hyperplastic polyposis syndrome

Hyperplastic Polyposis (HPPS) is a poorly characterized syndrome that increases colorectal cancer (CRC) risk. We aimed to provide a molecular classification of HPPS. We obtained 282 tumours from 32 putative HPPS patients with >or= 10 hyperplastic polyps (HPs); some patients also had adenomas and CRCs. We found no good evidence of microsatellite instability (MSI) in our samples. The epithelium of HPs was monoclonal. Somatic BRAF mutations occurred in two-thirds of our patients' HPs, and KRAS2 mutations in 10%; both mutations were more common in younger cases. The respective mutation frequencies in a set of 'sporadic' HPs were 18% and 10%. Importantly, the putative HPPS patients generally fell into two readily defined groups, one set whose polyps had BRAF mutations, and another set whose polyps had KRAS2 mutations. The most plausible explanation for this observation is that there exist different forms of inherited predisposition to HPPS, and that these determine whether polyps follow a BRAF or KRAS2 pathway. Most adenomas and CRCs from our putative HPPS patients had 'classical' morphology and few of these lesions had BRAF or KRAS2 mutations. These findings suggest that tumourigenesis in HPPS does not necessarily follow the 'serrated' pathway. Although current definitions of HPPS are sub-optimal, we suggest that diagnosis could benefit from molecular analysis. Specifically, testing BRAF and KRAS2 mutations, and perhaps MSI, in multiple polyps could help to distinguish HPPS from sporadic HPs. We propose a specific model which would have diagnosed five more of our cases as HPPS compared with the WHO clinical criteria.

[Emerging concepts in colorectal serrated polyps]

Colorectal serrated polyps are heterogeneous epithelial lesions characterized by a serrated architecture. They include the classical hyperplastic polyps and the much rarer serrated adenomas and mixed polyps. Whereas serrated adenomas are composed of an unequivocal adenomatous epithelium with architectural serrated, mixed polyps include two separate hyperplastic and adenomatous components. During the past few years, another type of serrated polyp with only very subtle proliferation abnormalities has been described. These atypical serrated polyps may occur either sporadically or in the context of colorectal polyposis. Despite their close resemblance to traditional hyperplastic polyps, some authors argued that they should be regarded as authentically neoplastic lesions and have proposed to call them "sessile serrated adenomas". Their malignant potential requires their removal when discovered during colonoscopy. This article reviews the histological features, the endoscopic appearance, the natural history and the molecular phenotype of the different categories of serrated polyps and introduces the concept of "serrated neoplastic pathway" in the development of colorectal cancer.

Colorectal serrated adenocarcinoma

Colorectal cancer (CRC) ranks among the three most common cancers in terms of both cancer incidence and cancer-related deaths in most Western countries. Serrated adenocarcinoma is a recently described, distinct variant of CRC, accounting for about 7.5% of all CRCs and up to 17.5% of most proximal CRCs. It has been postulated that about 10-15% of sporadic CRCs would have their origin in serrated polyps that harbour a significant malignant potential. These lesions include hyperplastic-type aberrant crypt foci, hyperplastic polyps, sessile serrated adenomas, admixed polyps and serrated adenomas, and constitute the so-called 'serrated pathway', which is distinct from both the conventional adenoma-carcinoma pathway and the mutator pathway of hereditary non-polyposis CRC and is characterized by early involvement of oncogenic BRAF mutations, excess CpG island methylation (CIM) and subsequent low- or high-level DNA microsatellite instability (MSI). Methylation of hMLH1 is likely to explain the increased frequency of high-level MSI (16%) and methylation of MGMT is postulated to explain the low-level MSI (29%) in serrated adenocarcinomas. Reproducible histopathological criteria for serrated adenocarcinoma have recently been established and they have been qualified by DNA expression analysis for 7928 genes, showing clustering of serrated adenocarcinomas into a molecular entity apart from conventional adenocarcinoma, and representing with distinct down-regulation of EPHB2, PTCH and up-regulation of HIF1alpha.

Endoscopic mucosal resection of large hyperplastic polyps in 3 patients with Barrett’s esophagus

AIM: To report the endoscopic treatment of large hyperplastic polyps of the esophagus and esophago-gastric junction (EGJ) associated with Barrett’s esophagus (BE) with low-grade dysplasia (LGD), by endoscopic mucosal resection (EMR).

METHODS: Cap fitted EMR (EMR-C) was performed in 3 patients with hyperplastic-inflammatory polyps (HIPs) and BE.

RESULTS: The polyps were successfully removed in the 3 patients. In two patients, with short segment BE (SSBE) (≤ 3 cm), the metaplastic tissue was completely excised. A 2 cm circumferential EMR was performed in one patient with a polyp involving the whole EGJ. A simultaneous EMR-C of a BE-associated polypoid dysplastic lesion measuring 1 cm x 10 cm, was also carried out. In the two patients, histologic assessment detected LGD in BE. No complications occurred. Complete neosquamous re-epithelialization occurred in the two patients with SSBE. An esophageal recurrence occurred in the remaining one and was successfully retreated by EMR.

CONCLUSION: EMR-C appears to be a safe and effective method for treating benign esophageal mucosal lesions, allowing also the complete removal of SSBE.

Hyperplastic polyposis syndrome: phenotypic presentations and the role of MBD4 and MYH

BACKGROUND & AIMS

Hyperplastic polyposis syndrome (HPS) is defined phenotypically with multiple, large and/or proximal hyperplastic polyps. There is no known germ-line predisposition. We aimed to characterize the clinicopathologic features of 38 patients with HPS and explore the role of germ-line mutations in the base excision repair genes MBD4 and MYH.

METHODS

Utilizing clinical databases of The Royal Melbourne Hospital Bowel Cancer Surveillance Service and the Familial Cancer Clinic, 38 patients with HPS were recruited. The patients were analyzed for age at first diagnosis, features of hyperplastic polyposis, family histories of polyposis and colorectal cancer (CRC), coexisting adenomas, serrated adenomas, incidence of CRC, and microsatellite instability in the tumours. Mutation analysis of MBD4 and MYH were performed.

RESULTS

Serrated adenomas were common (26%), and 19 (50%) of the 38 patients had a first-degree relative with CRC. Family history of HPS was uncommon, with only 2 cases found. Ten patients developed CRC, and 3 required surgery for polyposis. No pathogenic mutations in MBD4 were detected in the 27 patients tested, but 6 single nucleotide polymorphisms of uncertain functional significance were identified. Pathogenic biallelic MYH mutations were detected in 1 patient.

CONCLUSIONS

Mutations in MBD4 are unlikely to be implicated in HPS; MYH mutations should be studied, especially when adenomas occur in the same patient. The clinical, histopathologic, and molecular findings of this study should contribute to our understanding of HPS and its relationship to the serrated neoplasia pathway.

Distribution and prevalence of colorectal hyperplastic polyps using magnifying pan-mucosal chromoendoscopy and its relationship with synchronous colorectal cancer: prospective study

BACKGROUND AND AIM

Patients with multiple (hyperplastic polyposis) or large hyperplastic polyps (HPs) predominantly in the right-sided colon, have been reported to have an increased risk of colorectal cancer (CRC). This prospective study was conducted to clarify the distribution of various sized HPs using magnifying pan-mucosal chromoendoscopy and its relationship with synchronous CRC.

METHODS

Patients eligible for this study had an initial total colonoscopy. Indigo carmine dye was sprayed throughout the whole colon and rectum, and diagnoses were made using magnifying colonoscopy.

RESULTS

A total of 263 patients were enrolled, and a total of 3060 HPs were observed in 226 (86%) patients. The prevalence of patients with intermediate size (> or = 6 mm) HPs was 8.7% (n = 23) and that of patients with large HPs (> or = 10 mm) was 0.8% (n = 2). Of 3060 HPs, the numbers of diminutive (< 6 mm), intermediate size and large HPs were 3020, 38 and two, respectively, and 5.0%, 42.1% and 100% of these were located in the right-sided colon, respectively. Synchronous CRC was observed in 64 (24%) of 263 patients. Compared to patients without HPs, patients with intermediate size HPs showed a significant increase in odds ratio (OR) for synchronous CRC (OR = 4.9: 95% CI [1.3-18.2]), but there was no significant association between synchronous CRC and patients with diminutive or large HPs.

CONCLUSIONS

Compared to diminutive HPs, intermediate size and large HPs were predominantly located in the right-side colon. Moreover, intermediate size HPs were significantly correlated with synchronous CRC.

Hyperplastic polyposis and the risk of colorectal cancer

PURPOSE

Hyperplastic polyps are usually considered to be an innocent finding with little or no potential to progress to colorectal cancer. However, recent literature suggests that some of these polyps may be morphologically and genetically distinct and lead to microsatellite unstable colorectal cancers. The purpose of this study was to define the cancer risk associated with hyperplastic polyposis.

METHODS

All patients with hyperplastic polyposis diagnosed by a single colorectal surgeon at a university hospital were followed prospectively. The diagnosis of hyperplastic polyposis was made by the presence of more than 20 hyperplastic polyps distributed throughout the colon and/or a hyperplastic polyp at least 1 cm in size in diameter in the right colon. Patient demographics, family history, size, location, and distribution of polyps and the development of colorectal cancer were noted.

RESULTS

Thirteen patients who met the criteria for hyperplastic polyposis were identified and followed prospectively. All of these patients had at least 30 polyps distributed throughout the colon, often > 100. Nine of 13 also had a hyperplastic polyp at least 1 cm in size, usually in the right colon. Of particular note, 7 of 13 patients (54 percent) were diagnosed with colorectal cancer during the study period. Four had cancer on initial diagnosis and three patients developed cancer despite frequent colonoscopic surveillance. Five of seven colorectal cancers were located in the right colon.

CONCLUSIONS

Patients with hyperplastic polyposis are at high risk for colorectal cancer. Failure to identify this subset of patients could have dire consequences.

Phenotypic characteristics and risk of cancer development in hyperplastic polyposis: case series and literature review

OBJECTIVES

Hyperplastic polyposis (HP) is a poorly understood condition. The aim of this study is to describe the phenotype and the risk of cancer in HP.

METHODS

Patients with HP, as defined by the WHO International Classification, were identified through the University of Utah and the Huntsman Cancer Institute databases. Family history was retrieved when possible.

RESULTS

Fifteen patients were identified (10 M, 5 F) with a mean age at diagnosis of 52.6 +/- 16.4 yr (18-71). Sixty-five colonoscopies were performed (2-11 per person). A median of 90 polyps (16-210) per person and 15 polyps (range, 0-100) per procedure were reported. The median follow-up was 33 months (3-133); no cancer occurred during this period. Polyps were more frequent in the distal than the proximal colon (74%vs 26%; p < 0.001). The median polyp size was 4 mm (1-40 mm). Fifty-one hyperplastic polyps >10 mm were identified in 10 patients (38 proximal, 13 distal; p= 0.089). Forty-eight adenomas were found in 11 patients and were uniformly distributed. Serrated adenomas (n = 3) were found in one patient. A unique patient had 20 large hyperplastic polyps, 24 adenomas, 3 serrated adenomas, and 118 hyperplastic polyps. None of the patients had a first-degree relative with colon cancer.

CONCLUSIONS

In HP, hyperplastic polyps are more frequently distal colonic, and vary greatly in size and number. Most patients also develop adenomas that are distributed throughout the colon. No cancers developed within 3 yr of follow-up. Colonoscopic surveillance at intervals of 1-3 yr, depending upon the number and size of both adenomatous and hyperplastic polyps, appears prudent.

Management of Portuguese patients with hyperplastic polyposis and screening of at-risk first-degree relatives: a contribution for future guidelines based on a clinical study

BACKGROUND

Hyperplastic polyposis (HP) is a rare condition characterized by the presence of multiple hyperplastic polyps in the colon, which has been associated to an increased risk of colorectal cancer (CRC). Guidelines for management of this disease remain, so far, undefined.

AIMS

To evaluate, in symptomatic patients with HP, phenotypic characteristics as well as results of a screening program in their at-risk first-degree relatives.

PATIENTS

Pedigree information and clinical and endoscopic data of 14 patients with HP was studied. SEVENTEEN AND METHODS: at-risk first-degree relatives from six families were also invited to perform screening colonoscopy.

RESULTS

Twelve of fourteen (86%) patients had fewer than 100 colorectal polyps. Polyps' sizes ranged from 2 to 25 mm and were uniformly distributed through the whole colon in 43% of the patients. Hyperplastic polyps predominated, but 11/14 (79%) patients also harbored serrated as well as classic adenomatous polyps. CRC was present in 6/14 (43%) of the patients at the time of diagnosis. Familial history of CRC/polyps was positive in 6/12 (50%) of cases. Colonoscopy in at-risk relatives disclosed polyps in 10/17 (59%) of cases with at least one additional patient having criteria for HP.

CONCLUSIONS

Although small, this series demonstrates that a high level of suspicion is needed to diagnose the HP syndrome, in which serrated adenomas seem to be the hallmark. Although an elevated percentage of CRC was observed in this series of symptomatic patients with HP, prospective studies in asymptomatic individuals are needed to clearly quantify the risk of CRC in patients with HP. Because familial aggregation of HP was present in 3/12 (25%) of kindreds, screening colonoscopy should be offered to first-degree relatives.

The relationship between hypomethylation and CpG island methylation in colorectal neoplasia

Tumors are often characterized by an imbalance in cytosine methylation as manifested both by hypermethylation of CpG islands and by genome hypomethylation. These epigenetic changes were assessed in colorectal neoplasia to determine whether they arose through a common mechanism or indeed were distinct and unrelated phenomena. Fresh representative samples of adenomas, hyperplastic polyps, colorectal cancers, and normal mucosa were used in this study. Global methylation levels were measured by analyzing the methyl-accepting capacity of DNA. Methylation of p16, hMLH1, and MINT 1, 2, 12, and 31 were assessed by bisulfite polymerase chain reaction. Microsatellite status was determined by polymerase chain reaction using six markers and hMLH1 and proliferating cell nuclear antigen expression was assessed by immunohistochemistry. Normal colonic mucosa had a higher endogenous 5-methyl cytosine content than all proliferative lesions of the colon (P < 0.001). The extent of demethylation in hyperplastic polyps and adenomas was significantly related to its proliferative rate. Right-sided hyperplastic polyps were more likely to be methylated than adenomas (odds ratio, 2.3; confidence interval, 1.1 to 4.6). There was no relationship between the level of global hypomethylation and hypermethylation. Some hyperplastic colorectal polyps have a propensity to develop dense CpG island methylation. Hypermethylation and hypomethylation contribute separately to the process of carcinogenesis.

Single flexible sigmoidoscopy screening to prevent colorectal cancer: baseline findings of a UK multicentre randomised trial

BACKGROUND

This randomised controlled trial is examining the hypothesis that a single flexible sigmoidoscopy screening offered at around age 60 years can lower the incidence and mortality of colorectal cancer. We report here on acceptability, safety, feasibility, and yield.

METHODS

Men and women aged 55-64 years, in 14 UK centres, who responded to a mailed questionnaire that they would attend for flexible sigmoidoscopy screening if invited, were randomly assigned screening or control (ratio one to two). The control group was not contacted. Small polyps were removed during screening, and colonoscopy was undertaken if high-risk polyps (three or more adenomas, size 1 cm or greater, villous, severely dysplastic, or malignant) were found.

FINDINGS

Of 354,262 people asked about their interest in having flexible sigmoidoscopy screening, 194,726 (55%) responded positively, and 170,432 eligible individuals were randomised. Attendance among those assigned screening was 71% (40,674 of 57,254). 2131 (5%) were classified as high-risk and referred for colonoscopy; 38,525 with no polyps or only low-risk polyps detected were discharged. Distal adenomas were detected in 4931 (12.1%) and distal cancer in 131 (0.3%). Proximal adenomas were detected in 386 (18.8% of those undergoing colonoscopy) and proximal cancer in nine cases (0.4%). 62% of cancers were Dukes' stage A or locally excised. There was one perforation after flexible sigmoidoscopy and four after colonoscopy. An average of 48 people were screened, and two or three colonoscopy referrals generated, per centre each week. Interpretation Our flexible sigmoidoscopy screening regimen is acceptable, feasible, and safe. The prevalence of neoplasia is high, and colonoscopy referral rates of 5% are acceptable.

Review article: the non-inherited gastrointestinal polyposis syndromes

The non-inherited gastrointestinal polyposis syndromes represent a group of rare disorders characterized by the presence of multiple, non-adenomatous polyps on the gastrointestinal mucosa occurring in unrelated patients. We present here a review of the clinical and histo- pathological aspects of the syndromes to include the Cronkhite-Canada syndrome, hyperplastic polyposis and lipomatous polyposis. While infrequently encountered, these diseases can have devastating clinical effects that may be aggravated by delays in diagnosis and treatment. Prompt accurate diagnosis and treatment of these uncommon disorders depend on a sound working knowledge of the distinct clinical and pathological features described herein.

Hyperplastic polyposis: association with colorectal cancer

Hyperplastic polyposis is a loosely defined syndrome initially thought not to confer a clinically important predisposition to colorectal cancer. The aim of the current study was to examine the clinical, histologic, and molecular features of a prospective series of cases meeting a strict definition of the condition. Twelve patients were identified, seven of whom had developed colorectal cancer. Most polyps were hyperplastic, but 11 patients also had polyps containing dysplasia as either serrated adenomas. mixed polyps, or traditional adenomas. The mean percentage of dysplastic polyps in patients with cancer was 35%, and in patients without cancer, 11% (p < 0.05). Microsatellite instability (MSI) was present in 3 of 47 hyperplastic polyps and two of eight serrated adenomas. Kras was mutated in 8 of 47 hyperplastic polyps and two of eight serrated adenomas. No polyps showed loss of heterozygosity of chromosomes 5q, 1p, or 18q. Two of seven cancers showed a high level of MSI. It is concluded that hyperplastic polyposis is associated with a high risk of colorectal cancer. Hyperplastic polyps are the dominant type of polyp, but most cases have some dysplastic epithelium. A higher proportion of dysplastic polyps is associated with increased cancer risk. Clonal genetic changes are observed in some hyperplastic polyps and serrated adenomas.

Colorectal carcinomas arising in the hyperplastic polyposis syndrome progress through the chromosomal instability pathway

The hyperplastic polyposis syndrome is characterized by the presence within the colon of multiple large hyperplastic polyps. We describe a case of hyperplastic polyposis syndrome associated with two synchronous carcinomas, one of which arises within a pre-existing hyperplastic lesion. Comparative genomic hybridization was used to determine genetic changes in both carcinomas and several associated hyperplastic lesions. Microsatellite analysis at five loci was performed on carcinomas and representative hyperplastic polyps, and p53 status was analyzed by immunohistochemistry. Both carcinomas showed multiple genetic aberrations, including high level gains of 8q and 13q, and loss of 5q. These changes were not seen in the hyperplastic polyps. Microsatellite instability was not seen in the carcinomas, four separate hyperplastic polyps, the hyperplastic polyp with mild adenomatous change associated with the carcinoma, or a separate serrated adenoma. Allelic imbalance in the cancers at D5S346 and D17S938 suggested allelic loss of both p53 and APC, as well as at the loci D13S263, D13S174, D13S159, and D18S49. An early invasive carcinoma in one hyperplastic polyp stained for p53 protein, but the associated hyperplastic polyp was negative. In this case, neoplastic progression followed the typical genetic pathway of common colorectal carcinoma and occurred synchronously with mutation of p53.

Serrated adenoma of the colorectum: colonoscopic and histologic features

BACKGROUND

Serrated adenoma is a recently recognized epithelial neoplasm of the colorectum. The aim of this study is to clarify the colonoscopic features of serrated adenomas.

METHODS

The endoscopic findings for 52 serrated adenomas of the colorectum were investigated; these were then divided into three groups according to surface features. The histologic type (tubular, tubulovillous or villous) and the incidence of high-grade dysplasia were compared among the three groups.

RESULTS

The surface under chromoscopy showed a hyperplastic pattern in 17 lesions, a cerebriform pattern in 18 lesions and a combined pattern in 17 lesions. The tubular type of serrated adenoma was predominant in the hyperplastic pattern group (94%), whereas the tubulovillous or villous histologic types were frequent in the cerebriform pattern (89%) and combined pattern (82%) groups. High-grade dysplasia was found in 18% of the combined pattern adenomas; the incidence was lower in hyperplastic (6%) or cerebriform pattern (0%) adenomas.

CONCLUSIONS

Surface features of serrated adenomas have a close correlation with their histologic type. A combined hyperplastic-cerebriform surface pattern under chromoscopy was seen only in serrated adenomas.