Small bowel carcinoid tumour

Case contributed by Dr Henry Knipe

Presentation

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

Patient Data

Age: 90 years
Gender: Male
Modality: CT

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

Modality: Nuclear medicine

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

The patient proceeded to small bowel resection. 

HISTOPATHOLOGY

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 tumour which invades through muscularis propria into mesenteric fat 75x57x45mm. The tumour extensively abuts the serosa.

MICROSCOPIC DESCRIPTION: Sections show small bowel with two invasive tumours 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. Tumour has an infiltrative edge and both tumours invade through muscularis propria into perienteric tissue and mesenteric fat. Lymphovascular and perineural invasion are present. Both tumours are within 0.1mm of the serosa however serosal invasion is not present. The larger tumour is more than 10mm from both proximal and distal margins and the smaller tumour is 7mm from one longitudinal margin (inked green). Tumour cells are chromogranin+, synaptophysin+, CD56- and <1% of tumour cells are Ki67+. There are four lymph nodes, with two involved by metastatic tumour.

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

Case Discussion

The small bowel is one of the most (if not the most) location for carcinoid tumours. 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. 

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Case Information

rID: 42873
Case created: 12th Feb 2016
Last edited: 13th Feb 2016
Inclusion in quiz mode: Included

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