Adenocarcinoma of the small bowel

Last revised by Calum Worsley on 30 Sep 2022

Primary adenocarcinoma of the small bowel is about 50 times less common than colonic carcinoma.

Almost 50% of small bowel adenocarcinomas are found in the duodenum, especially near the ampulla. In the remaining cases, the jejunum is more commonly involved than the ileum1.

Risk factors include a history of:

More distal small bowel adenocarcinomas are more likely to be annular, duodenal adenocarcinomas tend to be papillary or polypoid1.

CT shows a soft-tissue mass with heterogeneous attenuation, usually with moderate enhancement after intravenous administration of contrast material.

The mass may manifest as an annular narrowing with abrupt concentric or irregular “overhanging edges,” a discrete tumor mass or an ulcerative lesion.

Usually, only a short segment of the bowel is involved. Gradual narrowing of the lumen leads to partial or complete small bowel obstruction 1.

A large, aggressive, ulcerated adenocarcinoma can be mistaken for lymphoma. However, lymph node metastases in adenocarcinoma are usually less bulky than those in lymphoma.

Small bowel malignant tumors:

Small bowel benign tumors:

  • adenomatous polyp

  • villous adenoma

  • leiomyoma

  • lipoma

  • hamartoma

  • hemangioma

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Cases and figures

  • Figure 1: intraoperative photograph
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  • Case 1
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  • Case 2: mucinous adenocarcinoma with small bowel obstruction
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