Malignant Tumors in Colon

Abstract

Colorectal cancer is a common and lethal disease in the world. The vast majority of primary colorectal cancers are adenocarcinomas, and other histologic types, including signet ring cell carcinoma, squamous cell carcinoma, adenosquamous carcinoma, small-cell carcinoma, medullary carcinoma, and undifferentiated carcinoma, are rare. Rare malignancies, such as lymphomas, metastatic cancers, and carcinoid tumors, can involve the colon. By Japanese criteria, early colorectal cancer is defined as cancer cells confined to the mucosa or the submucosa regardless of lymph node metastasis. Advanced colorectal cancer is defined as cancer cells invading more than proper muscle. Because superficial submucosal cancer is a candidate for endoscopic treatment, it is important to evaluate the exact depth of invasion by endoscopy in early colorectal cancer to decide proper therapeutic strategy. In this chapter, morphological classification and characteristic features of endoscopic evaluation will be described to differentiate early colorectal cancers from advanced cancers.