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Quiz: Case 5 Answers

15. What is the salient abnormality?
Filling defect
Luminal dilatation

Spot film of the terminal ileum demonstrates a round filling defect.

16. From where is this mass likely arising?
Bowel lumen
Bowel mucosa
Bowel wall

The morphology of a filling defect can help to decipher its location. This mass demonstrates acute angles where it meets the bowel wall, suggesting a mucosal or submucosal location. Intramural (leiomyoma) and extrinsic masses demonstrate margins with more obtuse angles with the bowel wall.

17. What is the most common primary neoplasm of the small bowel?

Remember that small bowel tumors are relatively rare. However, carcinoid is the most common primary neoplasm of the small bowel, although its most common location is the appendix. The larger a carcinoid tumor is, the more likely it is to be malignant. Tumors less than 1 cm are rarely malignant. Carcinoid SYNDROME (flushing, diarrhea, and bronchospasm) can occur with metastasis to the liver. Metastases to the mesentery cause a desmoplastic reaction, resulting in the characteristic stellate, calcified mass.

Primary adenocarcinoma in the small bowel is most common in the duodenum, presenting frequently as concentric luminal narrowing (apple-core lesion). Leiomyoma and leiomyosarcoma (GIST) are relatively common GI tumors that present as solitary, or rarely multiple, filling defects. Large tumors can ulcerate. Lymphoma, the camelion of cancer, is one of the most common small bowel cancers and can present in a variety of ways (i.e. it should be on most of differential diagnosis lists).

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