Skip to content

    Colorectal Cancer Health Center

    Font Size

    Rectal Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Cellular Classification and Pathology of Rectal Cancer

    The World Health Organization (WHO) classification of tumors of the colon and rectum include the following:[1]

    Epithelial Tumors

    Recommended Related to Colorectal Cancer

    Colon Cancer Treatment: What You Need to Know

    When Jennifer Marrone of San Diego, CA, was diagnosed with stage IV colon cancer at age 30, she didn't just want to know what her treatment options were. "I wanted to know how they were going to affect my life," says Marrone, who's now 35. She was pleased when her oncologist at UC San Diego Health gave her several suggestions for medications and lifestyle changes, like adopting a diet free of animal protein. He also had copies of research studies to back up each potential therapy and treatment. "I...

    Read the Colon Cancer Treatment: What You Need to Know article > >


    • Tubular.
    • Villous.
    • Tubulovillous.
    • Serrated.

    Intraepithelial neoplasia (dysplasia) associated with chronic inflammatory diseases

    • Low-grade glandular intraepithelial neoplasia.
    • High-grade glandular intraepithelial neoplasia.


    • Adenocarcinoma.
    • Mucinous adenocarcinoma.
    • Signet-ring cell carcinoma.
    • Small cell carcinoma.
    • Adenosquamous carcinoma.
    • Medullary carcinoma.
    • Undifferentiated carcinoma.

    Carcinoid (well-differentiated neuroendocrine neoplasm)

    • Enterochromaffin (EC)-cell, serotonin-producing neoplasm.
    • L-cell, glucagon-like peptide and pancreatic polypeptide/peptide YY (PYY)-producing tumor.
    • Others.

    Mixed carcinoma-adenocarcinoma

    • Others.

    Nonepithelial Tumors

    • Lipoma.
    • Leiomyoma.
    • Gastrointestinal stromal tumor.
    • Leiomyosarcoma.
    • Angiosarcoma.
    • Kaposi sarcoma.
    • Melanoma.
    • Others.

    Malignant lymphomas

    Adenocarcinomas account for the vast majority of rectal cancers. Other histologic types of colorectal cancer account for an estimated 2% to 5% of colorectal tumors.[2]


    1. Hamilton SR, Aaltonen LA: Pathology and Genetics of Tumours of the Digestive System. Lyon, France: International Agency for Research on Cancer, 2000.
    2. Kang H, O'Connell JB, Leonardi MJ, et al.: Rare tumors of the colon and rectum: a national review. Int J Colorectal Dis 22 (2): 183-9, 2007.

    This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

    WebMD Public Information from the National Cancer Institute

    Last Updated: May 28, 2015
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
    Next Article:

    Today on WebMD

    Colorectal cancer cells
    The right diagnosis is the most important factor.
    man with a doctor
    Our health check will steer you in the right direction.
    sauteed cherry tomatoes
    Fight cancer one plate at a time.
    bladder cancer x-ray
    Do you know the warning signs?
    Colon vs Rectal Cancer
    New Colorectal Treatments
    can lack of sleep affect your immune system
    Cancer Facts Quiz
    Virtual Colonoscopy
    Picture of the Colon
    Vitamin D