A 54-year-old man is evaluated for episodic abdominal discomfort, bloating sensation, flatulence, and occasional diarrhea. He has no blood in the stool or weight loss. The patient has tried avoiding dairy products, but the symptoms did not improve. On examination, there is mild epigastric tenderness on deep palpation. Stool occult blood testing is positive. Histopathological evaluation of hyperemic mucosa seen during gastrointestinal endoscopy reveals hyperplasia of branched, tubular submucosal glands containing alkaline secretions. Which of the following areas is the most likely site of biopsy in this patient?

Question

A 54-year-old man is evaluated for episodic abdominal discomfort, bloating sensation, flatulence, and occasional diarrhea.  He has no blood in the stool or weight loss.  The patient has tried avoiding dairy products, but the symptoms did not improve.  On examination, there is mild epigastric tenderness on deep palpation.  Stool occult blood testing is positive.  Histopathological evaluation of hyperemic mucosa seen during gastrointestinal endoscopy reveals hyperplasia of branched, tubular submucosal glands containing alkaline secretions.  Which of the following areas is the most likely site of biopsy in this patient?

Quizplus · Accepted Answer

The integrity of the small intestinal mucosa depends on the complete and rapid neutralization of hydrochloric acid in gastric contents. This is accomplished by alkaline secretions from 2 primary sources: Submucosal (Brunner) glands secrete copious amounts of alkaline mucus into the duodenum. These glands are most numerous at the pylorus but may be found intermittently up to the ampulla of Vater. The ducts of these glands pass through the muscularis mucosa and terminate in the mucosal crypts (crypts of Lieberkühn). The epithelial cells of the pancreatic ductules and ducts produce watery secretions containing high concentrations of bicarbonate ions. The strongly alkaline pancreatic secretions are then emptied into the duodenum at the ampulla. Tactile stimulation of the duodenal mucosa and increased parasympathetic activity following meals induce bicarbonate secretion from the submucosal glands. In addition, the presence of acid in the duodenum and jejunum causes release of secretin from the mucosa, stimulating secretion of bicarbonate from the submucosal glands and pancreas. Excess gastric acid secretion, such as seen in Helicobacter pylori infection, can cause increased production of secretin that, over time, can lead to hyperplasia of the submucosal glands. (Choices A and C) The antrum of the stomach contains numerous pyloric glands that secrete copious mucus for protection of the mucosa. Gastric acid is primarily secreted by parietal cells of the oxyntic glands at the body and fundus of the stomach. (Choice D) The mucosal crypts in the jejunum contain goblet cells (secrete mucus) and enterocytes (secrete water and electrolytes). These secretions have only minimal bicarbonate content. (Choices E and F) Bicarbonate is secreted by epithelial cells in the ileum and colon to neutralize acid produced by colonic bacteria. However, this bicarbonate is secreted at the villi in the ileum and crypts in the colon, and submucosal glands are not present in these locations. Educational objective: Gastric acid is neutralized by bicarbonate from the submucosal glands of the duodenum (Brunner glands) and from pancreatic duct secretions. Chronic overproduction of gastric acid can lead to hyperplasia of the submucosal glands.

A 54-Year-Old Man Is Evaluated for Episodic Abdominal Discomfort, Bloating