Meckel diverticulum

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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

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.

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.

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.