EDITOR’S QUIZ: GI SNAPSHOT

Answer

From question on page 1671

Computed tomography (CT) (fig 1) showed loops of thick walled distal small bowel and a 3×2 cm non-calcified mass within the bowel mesentery, surrounded by streaky fibrosis. There was no associated lymphadenopathy. Appearances were in keeping with a small bowel carcinoid tumour.

The histology slide of the resected bowel and mesentery (fig 2 ▶) confirmed an infiltrating carcinoid tumour (right arrow) associated with sclerotic encasement and constriction of the mesenteric vessels (left arrow). This compromised the vascular supply leading to intestinal ischaemia, which was the cause for her symptoms rather than carcinoid syndrome.

Figure 2.

 Histology slide of the resected bowel and mesentery.

Diarrhoea is a common feature of carcinoid syndrome and relates to the production and systemic release of serotonin and other peptide hormones by hepatic metastases. However, this patient’s liver ultrasound was normal. Another well recognised complication of midgut carcinoids is sclerosis of the mesenteric vessels due to the direct effect of peptide secretion on the local blood vessels. This can result in bowel ischaemia or even infarction.

Chronic intestinal ischaemia has been found at laparotomy in up to one third of patients with advanced midgut carcinoids.¹ Techniques such as three dimensional CT angiography enable visualisation of the tumour and its relationship to the local vessels. Use of conventional angiography is diminishing but has a role when imaging studies are equivocal. Exploratory surgery is often required to confirm the diagnosis. Definitive management is surgical, with careful dissection of the vasculature and resection of the affected bowel and mesenteric segment. However, short bowel syndrome may result if extensive bowel resection is required. In selected cases, vascular bypass surgery has been successful in symptom palliation.²