Cellular Classification of Small Intestine Cancer
Tumors that occur in the small intestine include the following:
- Adenocarcinoma (majority of cases).
- Lymphoma (uncommon), which is usually of the non-Hodgkin type. (Refer to the PDQ summary on Adult Non-Hodgkin Lymphoma Treatment for more information.)
- Sarcoma (most commonly leiomyosarcoma and more rarely angiosarcoma or liposarcoma).
- Carcinoid. (Refer to the PDQ summary on Gastrointestinal Carcinoid Tumor Treatment for more information.)
- Gastrointestinal stromal tumors. (Refer to the PDQ summary on Gastrointestinal Stromal Tumors Treatment for more information.)
Approximately 25% to 50% of the primary malignant tumors in the small intestine are adenocarcinomas, and most occur in the duodenum. Small intestine carcinomas may occur synchronously or metachronously at multiple sites.
Leiomyosarcomas occur most often in the ileum.
Some 20% of malignant lesions of the small intestine are carcinoid tumors, which occur more frequently in the ileum than in the duodenum or jejunum and may be multiple.
It is uncommon to find malignant lymphoma as a solitary small intestine lesion.
- Small intestine. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 127-32.