Small bowel carcinoid tumor

Case contributed by Henry Knipe


Diarrhea and vomiting initially. Now increasing abdominal distension and bowels not open.

Patient Data

Age: 90 years
Gender: Male

Large mass in the small bowel mesentery with enlarged lymph nodes surrounding it. The anterior aspect of the mass is indistinguishable from a segment of mural thickening of the mid ileum in the right iliac fossa, which forms a focal transition point between dilated proximal left relatively collapsed distal small bowel. Contrast does pass beyond the transition, consistent with a partial rather than complete obstruction.

111In Octreotide

Nuclear medicine

The mesenteric mass is octreotide avid in keeping with a neuroendocrine tumor. Adjacent smaller mesenteric nodal involvement also shown.

The patient proceeded to small bowel resection. 


MACROSCOPIC DESCRIPTION: "Small bowel resection": A section of small bowel (570mm length, 30mm diameter) with attached mesentery up to 90mm. One longitudinal margin inked blue, opposite longitudinal margin inked green and serosa inked black. There are two masses. 300mm from the inked blue margin and 250mm from the inked green margin is a well demarcated rubbery yellow-tan tumor which invades through muscularis propria into mesenteric fat 75x57x45mm. The tumor extensively abuts the serosa.

MICROSCOPIC DESCRIPTION: Sections show small bowel with two invasive tumors comprising nests and trabeculae of epithelioid cells with small amounts of eosinophilic cytoplasm, round nucleoli with speckled chromatin and no nucleoli. Mitoses are rare (<1 per 10 HPF) and there is no necrosis. Tumor has an infiltrative edge and both tumors invade through muscularis propria into perienteric tissue and mesenteric fat. Lymphovascular and perineural invasion are present. Both tumors are within 0.1mm of the serosa however serosal invasion is not present. The larger tumor is more than 10mm from both proximal and distal margins and the smaller tumor is 7mm from one longitudinal margin (inked green). Tumor cells are chromogranin+, synaptophysin+, CD56- and <1% of tumor cells are Ki67+. There are four lymph nodes, with two involved by metastatic tumor.

DIAGNOSIS: Small bowel resection: Two foci of neuroendocrine tumor of distal ileum.

Case Discussion

The small bowel is one of the most (if not the most) location for carcinoid tumors. Only a minority (<10%) present with carcinoid syndrome. In the abdomen, they can present with a strong desmoplastic reaction with angulation of the bowel (lacking in this case). Octreotide scanning can be useful because uptake, along with typical imaging features, strongly suggest the diagnosis. 

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.