Meckel Diverticulum

Meckel diverticulum is a true congenital diverticulum arising from incomplete obliteration of the vitelline duct. It usually lies on the antimesenteric border of the ileum and contains all layers of the bowel wall.

Ectopic gastric mucosa is clinically important because acid secretion can ulcerate adjacent ileal mucosa and produce bleeding. Pancreatic and other ectopic tissues are less common.

Major complications are bleeding, diverticulitis, intussusception, volvulus around a mesodiverticular band, obstruction, incarceration within a Littre hernia and perforation.

Presentation depends on the complication.

Bleeding is often painless and may be substantial.

Diverticulitis resembles appendicitis with lower abdominal pain, fever and localised tenderness.

Obstruction may result from intussusception, volvulus, an internal hernia beneath a mesodiverticular band or entrapment of bowel.

Adults with symptomatic disease frequently present with obstruction or inflammation rather than classic paediatric bleeding.

A symptomatic Meckel diverticulum should be resected.

For a long narrow diverticulum with uncomplicated inflammation and a healthy base, simple diverticulectomy is appropriate.

Use wedge or segmental ileal resection when:

The base is broad or inflamed
Perforation involves the base
Adjacent ileum is compromised
There is significant bleeding from adjacent ileal ulceration
A tumour is present
Obstruction has damaged adjacent bowel.

In bleeding Meckel diverticulum, segmental ileal resection is often preferable because the acid related ulcer may be located in adjacent ileum rather than inside the diverticulum itself.

An incidentally discovered asymptomatic Meckel diverticulum does not mandate automatic resection. Factors favouring prophylactic resection include younger age, male sex, a long or broad diverticulum, a fibrous band, palpable abnormal tissue and an operation in which diverticulectomy adds little additional morbidity. The decision remains individualised.

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.

Meckel Diverticulum

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management