Types of Colorectal Histologies

The most common cancers in the colon and rectum are adenocarcinomas.

There are several dysplasia codes in ICD-O-3 that are categorized as in situ. Colorectal dysplasia’s are not reportable in the US, but they are reportable in Canada. Pathologists frequently use the term “severe dysplasia” or “high-grade dysplasia” in place of carcinoma in situ. Code carcinoma in situ only if the pathologist expressly states, “carcinoma in situ.”

The most common histology codes for colorectal are (excludes GIST and Neuroendocrine histologies)

ICD-O-3 code ICD-O-3.2 Description Notes
8140/3

 Adenocarcinoma, NOS
Adenocarcinoma in adenomatous polyps
Adenocarcinoma in any type of polyp		 There are several histology codes that are adenocarcinoma with polyps. For colorectal sites, these are to be coded as adenocarcinoma (8140/3) or adenocarcinoma in situ (8140/2). See the Solid Tumor Rules for more information (Registry Operations - SEER Registrars)
8140/2 Adenocarcinoma in situ  
8480/2 LAMN (for Appendix, C181)
HAMN (for Appendix, C181)		 Per the Solid Tumor Rules, “Effective 1/1/2022, LAMN becomes reportable and is coded 8480/2, unless the pathologist indicates invasive behavior, which is coded 8480/3. HAMN can be either /2 or /3 depending on the pathologist statement of behavior.”
8560/3 Adenosquamous carcinoma  
8480/3 Mucinous adenocarcinoma/carcinoma
Colloid adenocarcinoma/carcinoma
Mucoid adenocarcinoma/carcinoma
Mucus adenocarcinoma/ carcinoma		  
8480/3 High-grade pseudomyxoma peritonei
Invasive pseudomyxoma peritonei		 Low-grade pseudomyxoma peritonei is 8480/1 and is not reportable
8490/3 Signet ring cell adenocarcinoma  

Updated: June 24, 2025