Meckel diverticulum

Meckel diverticulum
Diagnosis in short
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.
  • 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:

• Appendicitis.

Gross

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

Image

• 

  Meckel diverticulum. (AFIP/WC)

Microscopic

Features:

• 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

• Gastric foveolar epithelium in a MD (radiographics.rsna.org).
• Gastric glands in a MD (radiographics.rsna.org).
• Pancreatic glands in a MD (radiographics.rsna.org).

See also

• Small intestine.