What ectopic tissue is commonly found in a Meckel diverticulum?
A. Gastric mucosaApproximately 60% of Meckel diverticula contain ectopic tissue, of which over 60% consists of gastric mucosa. Pancreatic acini are next most common, followed by pancreatic islets, endometriosis, and hepatobiliary tissues. Gastric mucosa can ulcerate and bleed, the etiology of which can be hard to determine unless the Meckel diverticulum is known.