Aneuploidia: Marker of malignant colorectal adenomatous polyps

Abstract

Due to the fact that colorectal cancer (CRC) usually develops from focal neoplastic lesions of adenomatous colorectal polyps, colorectal adenomas might be considered precancerous lesions and are resected endoscopically in order to prevent the progression to CRC by interrupting the adenoma-carcinoma sequence [1]. The histopathological features of adenomatous polyps classically regarded as risk factors for malignant transformation are associated with the size, grade of epithelial dysplasia and histological type [2]. One of the most important risk factors is the size of the polyp, as there is a >40% chance for a larger than 2 cm adenomatous polyp to be malignant [3]. According to the WHO 25% classification rule, colorectal adenomatous polyps are histologically classified as tubular, tubulo-villous and villous [4], the presence of extended villous features being associated with a greater risk of malignancy [3]. Dysplasia grading in adenoma is usually defined according to the revised Vienna classification of gastrointestinal epithelial neoplasia as either low-grade (epithelial neoplastic changes limited only to the epithelial glands) or high-grade (glandular irregularity and crowding with “back-to-back” glands, a cribriform architecture with prominent glandular budding) [5]. Highgrade dysplasia is usually associated with the development of CRC, but sometimes invasive carcinoma may stem from low-grade dysplasia.