Cellular Classification and Pathology of Rectal Cancer
Epithelial Tumors
Nonepithelial Tumors
The World Health Organization (WHO) classification of tumors of the colon and rectum include:[1]
Epithelial Tumors
Adenoma
- Tubular.
- Villous.
- Tubulovillous.
- Serrated.
Intraepithelial neoplasia (dysplasia) associated with chronic inflammatory diseases
- Low-grade glandular intraepithelial neoplasia.
- High-grade glandular intraepithelial neoplasia.
Carcinoma
- 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
Nonepithelial Tumors
- Lipoma.
- Leiomyoma.
- Gastrointestinal stromal tumor.
- Leiomyosarcoma.
- Angiosarcoma.
- Kaposi sarcoma.
- Melanoma.
- Others.
Malignant lymphomas
- Marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type.
- Mantle cell lymphoma.
- Diffuse large B-cell lymphoma.
- Burkitt lymphoma.
- Burkitt-like/atypical Burkitt lymphoma.
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]
References
-
Hamilton SR, Aaltonen LA: Pathology and Genetics of Tumours of the Digestive System. Lyon, France: International Agency for Research on Cancer, 2000.
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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.
[PUBMED Abstract]
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