Question

Describe the histological changes that occur in patients with Zollinger-Ellison Syndrome. What is the etiology of the disorder? How does the etiology of this disorder differ from that of gastroesophageal reflex disease? What protective mechanisms does the tissue employ to prevent the tissue damage observed in disorders mentioned above?

Answer 1

Zollinger Ellison Syndrome is a gastrinoma- Tumor that affects upper part of pancreas to produce gastrin leading to increased production of gastric acid(hypersecretion), ultimately causing peptic ulcer

ETIOLOGY: This can happen on its own or as a part of dominant syndrome called Multiple Endocrine Neoplasia Type 1(MEN1).The primary tumor is usually located in the pancreas,duodenum or abdominal lymph nodes. This is a gastrin secreting tumor found in the pancreas.Since gastrin is the hormone that stimulate the gastric acid secretion by the parietal cells of the stomach and by inducing the histamine release from ECL cells.Excess acid secretion in the stomach results in peptic ulcer disease with epigastric pain,coughing,bleeding ulcer and diarrhoea.It is most commonly associated with the multiple endocrine neoplasm (MEN- Tumor in Pituitary,Pathyroid and Pancreas).

Histologically, most gastrinoma are well differentiated neuroendocrine tumors with abundant neurosecretory granules.The ectopic endocrine gastrin secreting cells with fundic atrophy, hypertrophy of oxyntic mucosa,hyperplasia of parietal and mucous cells.In extreme cases, dysplasia can occur leading to true carcinoid tumor.

GERD is a condition of gastric acid moving into the wrong place(primarily up into the esophagus and mouth), as compared to stomach's hypersecretion of gastric acid, which leaks into surrounding tissues.

• Defective lower esophageal sphincter
• normally gastric contents don't back up into the esophagus because the esophageal sphincter creates enough pressure around the lower end of the esophagus to close it.
• Reflex occurs when LES pressure is deficient or pressure in the stomach exceeds Sphincteer pressure.
• When this happens,sphincter relaxes, allowing gastric contents to regurgitate into the esophagus.

In the stomach, the epithelium has mucosal defence mechanism to protect it from the hydrochloric acid.The pre - epithelial protection is made by mucus-bicarbonate barrier. The mucus and bicarbonate create the pH gradient making the epithelium to a neutral pH.Both are secreted by the mucus cells.