Colorectal polyp is one of the most common lesions encountered during colonoscopy. Some colorectal polyps are benign and others malignant. Colorectal polyps are classified into epithelial and nonepithelial polyps. Epithelial polyps include adenomatous polyp, serrated polyp, hamartomatous polyp, and inflammatory polyp. Endoscopic characteristics such as gross morphology and detailed surface features like pit pattern and microvascular pattern by image-enhanced endoscopy may help real-time histological diagnosis of epithelial polyps. Common nonepithelial polyps include neuroendocrine tumor, lipoma, leiomyoma, GIST, and lymphangioma. Differential diagnosis of nonepithelial polyps in the colorectum can be made by assessment of endoscopic features such as consistency, color, size, and location. Some patients show numerous polyps in the colorectum and/or in other parts of the gastrointestinal tract, which is called polyposis. Polyposis syndrome is classified into hereditary and nonhereditary polyposis.
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