All layers bowel wall are present in Meckel diverticulum, although the serosa is beyond the right image and not seen here.
Focal gastric heterotopia is present, as seen by a few parietal cells.
In the developing embryo, the vitelline duct connects the lumen of the gut to the yolk sac. Failure of this duct to obliterate leads a remnant called Meckel Diverticulum. This blind-ended outpouching of the gut is a true diverticulum, meaning it contains all layers of the bowel wall (Kumar).
The rule of 2s can be used to remember the key points about this vestigial remnant: 2 feet from the ileocecal value, 2 inches in length, 2% are symptomatic, usually presents at age 2 and males are 2 times more likely to be affected.
In approximately half the cases, there will be gastric and/or pancreatic heterotopia. This is an important fact because peptic ulceration can occur in this mucosa and lead to bleeding or symptoms that mimic acute appendicitis.
Although approximately 2% of the population have Meckel Diverticulum, only 5% are symptomatic. The classic presentation is painless rectal bleeding in a young child. In rare cases, perforation and intussusception have been documented (Rabinowitz).
Kumar V, Abbas AK, Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th Ed. Philadelphia, PA: Elsevier; 2005: 830.
Rabinowitz SS, Hongye Li. eMedicine: Meckel Diverticulum. Last updated on March 18, 2010. Available at: emedicine.medscape.com/article/931229-overview