[Histopathological diagnosis and differential diagnosis of colorectal serrated polys: findings of a consensus conference of the working group “gastroenterological pathology of the German Society of Pathology”]. Pathologe. 2011;32:76-82. [PMID: 20924763 DOI: 10.1007/s00292-010-1365-3]

Histological and molecular classification of gastrointestinal polyps

Endoscopic diagnosis and treatment for gastrointestinal polyps became widely available within the last decades. Exact terminology is important for further therapeutic steps, follow up or treatment. Gastroenterologists, Oncologists, Surgeons and Pathologists need to be aware of the most recent terminology to ensure proper risk assessment and subsequent treatment if necessary. This manuscript aims to list the variety of gastrointestinal polyps and the molecular background where appropriate.

Intraprocedural bowel cleansing with the JetPrep cleansing system improves adenoma detection

AIM: To investigate the impact of JetPrep cleansing on adenoma detection rates.

METHODS: In this prospective, randomized, crossover trial, patients were blindly randomized to an intervention arm or a control arm. In accordance with the risk profile for the development of colorectal carcinoma, the study participants were divided into high-risk and low-risk groups. Individuals with just one criterion (age > 70 years, adenoma in medical history, and first-degree relative with colorectal cancer) were regarded as high-risk patients. Bowel preparation was performed in a standardized manner one day before the procedure. Participants in the intervention arm underwent an initial colonoscopy with standard bowel cleansing using a 250-mL syringe followed by a second colonoscopy that included irrigation by the use of the JetPrep cleansing system. The reverse sequence was used in the control arm. The study participants were divided into a high-risk group and a low-risk group according to their respective risk profiles for the development of colorectal carcinoma.

RESULTS: A total of 64 patients (34 men and 30 women) were included in the study; 22 were included in the high-risk group. After randomization, 30 patients were assigned to the control group (group A) and 34 to the intervention group (group B). The average Boston Bowel Preparation Scale score was 5.15 ± 2.04. The withdrawal time needed for the first step was significantly longer in group A using the JetPrep system (9.41 ± 3.34 min) compared to group B (7.5 ± 1.92 min). A total of 163 polyps were discovered in 64 study participants who underwent both investigation steps. In group A, 49.4% of the polyps were detected during the step of standard bowel cleansing while the miss rate constituted 50.7%. Group B underwent cleansing with the JetPrep system during the first examination step, and as many as 73.9% of polyps were identified during this step. Thus, the miss rate in group B was a mere 26.1% (P < 0.001). When considering only the right side of the colon, the miss rate in group A during the first examination was 60.6%, in contrast to a miss rate of 26.4% in group B (P < 0.001).

CONCLUSION: JetPrep is recommended for use during colonoscopy because a better prepared bowel enables a better adenoma detection, particularly in the proximal colon.

Competition in Colon Cancer Screening? What Is the Role of Colonoscopy?

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. The incidence could be reduced if this cancer were to be diagnosed at an early stage of disease. A competition has started between the existing screening methods to be the most efficient in detecting premalignant conditions. This review illustrates the current state of screening techniques for CRC.

METHOD

Pubmed was searched for meta-analyses and prospective studies on screening for CRC, with an emphasis on colonography, computed tomographic colonography (CTC), magnetic resonance colonography (MRC), stool DNA testing, and colon capsule endoscopy, and critical appraisal of the research was done by the reviewers.

RESULTS

The imaging techniques (CTC and MRC) had similar detection rates for bigger lesions (≥10 mm) as colonoscopy. High-definition colonoscopy showed better efficiency with smaller lesions. The techniques developing around colonoscopy such as the retro-viewing colonoscope, the balloon colonoscope, or the 330-degree viewing colonoscope try to enhance efficacy by reducing the adenoma miss rate in right-sided, non-polypoid lesions. Colon capsule endoscopy and the stool detection systems are limited to identifying cancer but not necessarily adenomas.

CONCLUSION

Colonoscopy is the preferred CRC screening strategy and the undisputed gold standard in terms of efficacy.

Increased expression of α-methylacyl-coenzyme A racemase (AMACR; p504s) and p16 in distal hyperplastic polyps

Background

Hyperplastic polyps (HP) and sessile serrated adenomas (SSA) share morphological similarities. In this immunohistochemical study we chose a panel of potential relevant and promising biomarkers including α-methylacyl-coenzyme A racemase (AMACR; p504s), which is involved in the degradation of branched chained fatty acids derivates, and analysed a cohort of HPs and SSAs in order to identify different immunophenotypes in relation to lesion localisation.

Methods

154 specimen were carefully selected and a micro tissue array (TMA) was constructed. Immunohistochemistry of p16^Ink4a, Ki67, α-methylacyl-coenzyme A racemase (AMACR; p504s), BRAF, CK 20, MLH1 and β-catenin was performed and and immunoexpression was compared among proximal and distal HPs as well as SSAs.

Results

None of the markers revealed a differential expression among HPs and SSAs. However, the study demonstrates a significant overexpression of AMACR (p = 0.004) and p16^Ink4a (p = 0.028) in distal HPs compared to proximal HPs. In addition AMACR overexpression was associated with increased p16^Ink4a immunoexpression (p < 0.001).

Conclusions

In this study we describe differential AMACR and p16^Ink4a in HPs in relation to their localisation. Distal HPs were characterized by AMACR and p16^Ink4a overexpression in contrast to proximal HPs, although morphological identically. Thus AMACR overexpression points towards a pathobiological relevance of the protein in distal HPs. In context of recently published data this suggest distal HPs as potential precursor lesions of certain adenoma subtypes. However, at this point of time this finding remains speculative and needs to be confirmed by further studies.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1836116001066768

[Standardized and structured histopathological evaluation of colorectal polyps: a practical checklist against the background of the new WHO classification]

Gastroenterologists removing colorectal polyps expect standardized and well-structured pathological reports, providing them with all relevant data for the further clinical management of the patient. Over the last year, a task force of clinicians and pathologists has developed a checklist to improve and harmonize endoscopic and pathological reporting of colorectal polyps. This checklist concentrates more on concrete recommendations from evidence-based guidelines and established international classifications for daily practice rather than detailed molecular pathological pathways of carcinogenesis. These recommendations are based on the current S3 guidelines for colorectal cancer (the chapter entitled "Management of colorectal polyps"), the histomorphological consensus manuscript of the GI working group of the German Society for Pathology, as well as the current WHO classification for tumors of the digestive system.

CpG island methylation in colorectal cancer: past, present and future

The concept of a CpG island methylator phenotype, or CIMP, quickly became the focus of several colorectal cancer studies describing its clinical and pathological features after its introduction in 1999 by Toyota and colleagues. Further characterization of CIMP in tumors lead to widespread acceptance of the concept, as expressed by Shen and Issa in their 2005 editorial, "CIMP, at last." Since that time, extensive research efforts have brought great insights into the epidemiology and prognosis of CIMP+ tumors and other epigenetic mechanisms underlying tumorigenesis. With the advances in technology and subsequent cataloging of the human methylome in cancer and normal tissue, new directions in research to understand CIMP and its role in complex biological systems yield hope for future epigenetically based diagnostics and treatments.