Small Bowel Tumour

Small bowel tumours are uncommon and include adenocarcinoma, neuroendocrine tumour, gastrointestinal stromal tumour, lymphoma and less common mesenchymal or metastatic lesions. Histology determines both the operation and systemic treatment. Adenocarcinoma is particularly common in the duodenum, neuroendocrine tumours favour the distal ileum and gastrointestinal stromal tumours commonly arise in the jejunum or ileum.

Clinical behaviour ranges from an incidental small lesion to obstruction, bleeding, intussusception, perforation or metastatic disease.

Presentation is often delayed because the small bowel is difficult to investigate and early symptoms are nonspecific.

High value presentations include:

• Intermittent central abdominal pain
• Iron deficiency anaemia or occult gastrointestinal bleeding
• Recurrent partial bowel obstruction
• Unexplained weight loss
• Intussusception in an adult
• Palpable abdominal mass
• Perforation or overt bleeding in advanced disease

Neuroendocrine tumours may produce mesenteric fibrosis with bowel angulation and ischaemia. Carcinoid syndrome generally implies significant metastatic burden, most commonly hepatic metastases.

CT enterography: preferred for suspected mural small bowel tumour; define the lesion, obstruction, regional nodes and metastatic disease.

Capsule endoscopy: useful for occult bleeding or mucosal lesions but avoid when significant obstruction or stricture is suspected.

Device assisted enteroscopy: permits direct biopsy of lesions beyond conventional endoscopic reach.

Once histology is established, stage according to the specific tumour rather than applying one generic small bowel cancer pathway.

Resect symptomatic or potentially malignant localised tumours when an R0 resection is achievable.

For adenocarcinoma, perform segmental bowel resection with regional mesenteric lymphadenectomy.

For small bowel gastrointestinal stromal tumour, perform complete segmental resection with an intact pseudocapsule. Routine lymphadenectomy is unnecessary because nodal metastases are uncommon.

For ileal neuroendocrine tumour, resect the primary lesion and its associated mesenteric nodal disease while preserving mesenteric vascular supply where possible. Carefully inspect the entire distal small bowel because multifocal lesions are common.

Small bowel lymphoma is primarily treated according to histological subtype with systemic therapy. Surgery is reserved for perforation, uncontrolled bleeding, obstruction or a lesion requiring resection for diagnosis or source control.

An obstructing unresectable malignancy may require bypass, stenting where anatomically feasible or another palliative decompressive strategy.