Epidemiologia dos adenomas serrilhados em uma casuística do Hospital Alemão Oswaldo Cruz em São Paulo / Epidemiology of serrated adenomas in a German Hospital Oswaldo Cruzs series in São Paulo

Introdução: pólipos serrilhados representam um grupo heterogêneo de pólipos que são lesões precursoras para carcinomas colorretais serrilhados. Estes desenvolvem através da via serrilhada, caracterizada por metilação do DNA e mutação do gene BRAF. A classificação histológica dos pólipos serrilhados tem evoluído ao longo das duas últimas décadas para distinguir três subtipos: pólipo hiperplásico (PH), adenoma serrilhado séssil (ASS) e adenoma serrilhado tradicional (AST). Objetivos: avaliar a epidemiologia dos adenomas serrilhados em pacientes submetidos à colonoscopia no Hospital Alemão Oswaldo Cruz, em uma casuística, nos anos de 2013 e 2014. Métodos: foram avaliados 5720 pacientes submetidos à colonoscopia por diversas indicações, sendo que 139 deles tinham adenomas serrilhados. Resultados: a idade média dos pacientes que apresentaram adenomas serrilhados foi de 63 anos, sendo mais comum no sexo feminino. O segmento intestinal mais acometido foi o cólon direito e o tamanho médio dos adenomas foi de 0,2 cm, sendo mais comuns as lesões sésseis. Conclusão: os adenomas serrilhados possuem uma aparência endoscópica distinta dos adenomas convencionais, sendo muitas vezes sutil. Colonoscopia eficaz requer identificação precisa destas lesões e manejo adequado, já que possuem risco de evolução para câncer colorretal.

Introduction: serrated polyps represent a heterogeneous group of polyps that are precursor lesions to colorectal serrated carcinomas. These developed through the serrated means, characterized in DNA methylation and BRAF gene. The histological classification of serrated polyps have evolved over the past two decades to distinguish three subtypes: hyperplastic polyps (HP), sessile serrated adenoma (SSA) and traditional serrated adenoma (TSA). Aims: to evaluate the epidemiology of serrated adenomas in patients undergoing colonoscopy at the Hospital Alemão Oswaldo Cruz, by one single examinator, in the years 2013 and 2014. Methods: we evaluated 5720 patients undergoing colonoscopy for different indications, with 139 of them had serrated adenomas. Results: the mean age of patients with serrated adenomas was 63 years and is more common in females. The most affected intestinal segment was the right colon and the average size of adenomas was 0.2 cm, more common sessile lesions. Conclusion: the serrated adenomas have a distinctive endoscopic appearance of conventional adenomas, often subtle. Effective colonoscopy requires accurate identification of these lesions and appropriate management, as they have risk for developing colorectal cancer.

The expression and mutation of β-catenin in colorectal traditional serrated adenomas.

Context : Exon 3 mutation of β-catenin is associated with the carcinogenesis. Aims: In this study we aimed to detect the expression of exon 3 mutations of β-catenin in colorectal TSA, TA/VTA, and CRC. Materials and Methods : Immunohistochemistry staining for β-catenin was performed for 30 TSA, 20 tubular adenomas (TA)/villous tubular adenomas (VTA), and 21 colorectal carcinoma (CRC) cases. DNA sequencing of the exon 3 of β-catenin gene was performed for 8 TSA cases, 6 TA cases, 5 VTA cases, and 10 CRC cases with positive staining in the nuclei and cytoplasm. Statistical Analysis: A Fisher exact test and chi-square test were used to analyze the differentiations of the expression of β-catenin in TSA, TA/VTA, and CRC. Results : The percentages of β-catenin expression in TSA, TA/VTA, and CRC were 76.6% (23/30), 70.0% (14/20), and 95.2% (20/21), respectively, and were significantly different among these three types of tissue specimens (χ2 = 22.805, P < 0.001). Although β-catenin expression levels in TSA were not related to it in TA/VTA, they were significantly different between TSA/TA/VTA and CRC. The degree of dysplasia was well correlated with β-catenin expression (TSA: P < 0.01; TA/VTA: P < 0.05). But β-catenin exon 3 mutations were not detected in any of these tissue specimens. Conclusions : Aberrant β-catenin expression is associated with the degree of dysplasia in TSA. β-catenin likely plays an important role in the pathogenesis of colorectal TSA and conventional adenomas.

Adenomas aserrados: otro precursor de carcinoma de colon / Serrated adenoma: another precursor of colon cancer

En este estudio se describen 12 pacientes a quienes se le realizó Colonoscopia en el período de un año entre marzo 2009 y mayo 2010 (10/83,33% mujeres, 2/16,67% hombres) encontrándose lesiones planas, sésiles, sobre pliegues en colon derecho, patrón de Kudo I – II (criptas elongadas horizontalmente). La aplicación de la técnica de cromoscopia electrónica combinada con magnificación (FICE) constituye un área prometedora en la descripción de cambios patológicos mínimos de la mucosa y microvasculares. Permite incrementar la correlación entre las imágenes endoscópicas y los resultados histopatológicos. Los adenomas aserrados pueden constituir lesiones precursoras de carcinoma colorrectal con diferente secuencia a la clásica secuencia adenoma-carcinoma. Los estudios morfológicos y moleculares están identificando vías evolutivas relacionadas a metilación del ADN, mutación del BRAF e inestabilidad de microsatélites.

This study includes 12 consecutive patients who had a colonoscopy performed between Mar 2009 and May 2010 (10/83,33% females, 2/16,67% males), finding sessile lesion have a predilection for the proximal colon, pits patterns I – II (crypt dilatation and horizontal extension of crypts immediately above the muscularis mucosae). The application of this new technology electronic chromoendoscopy combined with high resolution endoscopy has promising areas of development in the description of pathologic mucosal changes and microvessels. This advanced technology allows an increased correlation between the images processed and the histological results. The serrated pathway neoplastic encompasses a morphologically and molecularly distinct group of colorectal neoplasms and represents an alternative molecular pathway to colorectal cancer. The sequence appears to begin with a non-dysplastic serrated polyp to a serrated adenoma and ultimately to carcinoma. Morphological and molecular studies are distinguishing a separate evolutionary pathway for colorectal cancer with extensive DNA methylation, mutation of BRAF and microsatellite instability.

Clinical Features of Colorectal Serrated Adenomas

PURPOSE: Colorectal cancer is believed to progress through an adenoma-carcinoma sequence. However, recent evidence increasingly supports the existence of an alternative route for colorectal carcinogenesis through a serrated adenoma, which combines the architectural features of hyperplastic polyps with the cytological features of traditional adenomas. We assessed the characteristics and the endoscopic features of serrated adenomas and compared them with those of hyperplastic polyps and traditional adenomas in Korea. METHODS: The medical records of 344 consecutive patients who underwent a colonoscopic biopsy or polypectomy from January 2003 through August 2004 at Gyeongsang National University Hospital were analyzed retrospectively. RESULTS: Serrated adenomas were seen in 12 cases (3.4%), and the most common site was the rectum (50%). Endoscopically in most cases, the serrated adenomas had small diameters (< or = 0.5 cm) and were single polyps. Morphologically, the serrated adenomas were flat and non-pedunculated. The coincidental rate of the carcinomas was 8.3%. CONCLUSIONS: According to this study, serrated adenomas are generally single, sessile adenomas with diameters less than 5 mm, and they are commonly observed in the left colon, especially in the rectum.