Synchronous Triple Colon Carcinoma Exhibiting Various Histologies, Report of a Case

We report a case of synchronous triple colon carcinoma on the transverse colon exhibiting various histologies of moderately differentiated adenocarcinoma (first carcinoma) and mucinous carcinoma (second carcinoma), and poorly differentiated adenocarcinoma (third carcinoma). A 45-year-old man was admitted to our hospital because of a positive fecal occult blood test. As two type 2\u27 carcinomas on the transverse colon were detected by colonoscopy, left hemicolectomy was performed under the diagnosis of multiple transverse colon carcinomas in August, 1990. Macroscopic examination of the resected transverse colon specimen revealed that there were two type 2 carcinomas and one type Hb carcinoma on the transverse colon of the oral side, but the type lib carcinoma was undetected before operation. Histological examination revealed that the type 2 carcinoma of the oral side was a moderately differentiated adenocarcinoma infiltrating the serosal layer (first carcinoma), and type 2 carcinoma of the anal side was a mucinous carcinoma invading the muscularis propria (second carcinoma), and type Hb carcinoma was a poorly differentiated adenocarcinoma with intramucosal invasion (third carcinoma) . As this case is synchronous triple colon carcinoma exhibiting various histologies, we consider this case to have various patterns of tumorigenesis