Meckel diverticulum

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Meckel diverticulum (also Meckel's diverticulum), is congenital structure of the distal small bowel that occasionally gets inflamed and may present with acute appendicitis-like symptoms.

Meckel diverticulum
Diagnosis in short

Gross image of a Meckel diverticulum. (AFIP/WC)

LM small bowel mucosa, +/-gastric mucosa (foveolar epithelium, oxyntic mucosa), +/-pancreatic epithelium
Gross small bowel outpouching on antemesenteric aspect ~5 cm long, ~60 cm from the ileocecal valve
Site small intestine

Symptoms abdominal pain
Prevalence uncommon ~2% of population
Prognosis benign
Clin. DDx acute appendicitis, other causes of abdominal pain
Treatment surgical removal

General

  • Most common congenital anomaly of the gastrointestinal tract.[1]
    • Remnant of the omphalomesenteric duct - a connection of the yolk sac and midgut.

The rule of 2s:

  • 2 feet from the terminal ileum
  • 2% of the population
  • 2% symptomatic.
  • 2 inches long.
  • 2 year old.
  • 2 types of epithelium - gastric and pancreatic.

Main clinical DDx of a symptomatic Meckel diverticulum:

Gross

  • Antimesenteric attachement, i.e. a Meckel's diverticulum hangs off the side opposite of the mesentery.

Image

Microscopic

Features:[1]

  • Small bowel mucosa.
  • +/-Gastric mucosa:
    • Foveolar epithelium: champagne flute-like columnar epithelium.
    • Oxyntic mucosa: parietal cells (pink) and chief cells (purple).
  • +/-Pancreatic epithelium:
    • Pancreatic acini.

Images

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Small bowel with Meckel's diverticulum, Excision:
    - Benign small bowel diverticulum with focal active inflammation and reactive 
      lymphoid hyperplasia at tip, compatible with clinical impression of 
      inflamed Meckel's diverticulum. 
    - Unremarkable small bowel wall at resection margin.

See also

References

  1. 1.0 1.1 Levy, AD.; Hobbs, CM.. "From the archives of the AFIP. Meckel diverticulum: radiologic features with pathologic Correlation.". Radiographics 24 (2): 565-87. doi:10.1148/rg.242035187. PMID 15026601.