GIT 3 Flashcards
(15 cards)
What are the gross features of a chronic peptic ulcer?
• The gastric antrum and first portion of the duodenum are the commonest sites.
• Ulcer penetrates the submucosa and even muscle.
• Most are solitary, round to oval, sharply punched out craters 2 to 4 cm in diameter.
• The base of the crater appears clean and smooth.
What are the four histological layers of a chronic peptic ulcer?
- Necrotic debris
- Nonspecific acute inflammatory cells
- Granulation tissue
- Fibrosis
What are the defense forces that protect the gastric mucosa?
• Mucous layer and bicarbonate secreted by epithelium.
• Regenerative capacity of epithelial cells.
• Elaboration of Prostaglandin.
• Mucosal blood flow.
What are the damaging forces that contribute to chronic peptic ulcers?
• ↑ amount of HCl secretion (gastric hyperacidity).
• Infection by H. Pylori.
• Use of NSAIDs.
• Smoking & alcohol.
What is Zollinger-Ellison syndrome, and how does it relate to peptic ulcers?
Zollinger-Ellison syndrome is a tumor of the pancreas or other part of the small intestine associated with excessive secretion of gastrin and hence excess acid secretion, causing multiple ulcers in the stomach, duodenum, and even jejunum.
What are the complications of chronic peptic ulcers?
- Bleeding: Most frequent complication, occurs in 15% to 20% of patients.
- Perforation (5%): Causes escape of gut contents into the peritoneal cavity → acute peritonitis.
- Healing by scarring: Contraction of fibrous scar, e.g., Pyloric obstruction.
- Malignant transformation: Occurs in less than 1% in gastric ulcer and never occurs in duodenal ulcer.
What are the types of gastric tumors?
• Benign: Polyps (Hyperplastic 75%, fundic 15%, and adenomatous 10%), Leiomyomas, Lipomas.
• Malignant: Adenocarcinoma (90-95%), Lymphoma (MALTomas).
• Potentially malignant: G.I.S.T (Gastro-Intestinal Stromal Tumor), Carcinoid (Neuroendocrine tumor).
What are the characteristics of hyperplastic and inflammatory polyps?
• Usually arising in a background of chronic gastritis that initiates the injury and reactive hyperplasia that causes polyp growth.
• The frequency of dysplasia in this polyp correlates with size (polyps larger than 1.5 cm in size have an increased risk).
What are fundic gland polyps, and who are they common among?
• Fundic gland polyps are common among people who regularly take proton pump inhibitors to reduce stomach acid.
What are adenomatous polyps, and what is their potential risk?
• Adenomatous polyps are true benign neoplasms and may turn into carcinomas, particularly if they exhibit dysplasia on biopsy.
What are the risk factors for gastric carcinoma?
- Environmental: High intake of alcohol and smoking, nitrate or nitrite in the food.
- Epstein–Barr virus (EBV): Associated with 10% of adenocarcinoma.
- Pre-malignant conditions (Host factor): Gastric adenoma, H. pylori associated gastritis.
- Genetic factors: Blood group A has a high incidence for gastric carcinoma.
What are the gross features of gastric adenocarcinoma?
- Exophytic: Large fungating mass.
- Ulcerative: The border of the ulcer is nodular and beaded, irregular, not demarcated from the surrounding tissue.
- Diffuse infiltrating: The wall, causing marked thickening and loss of elasticity (leather bottle or linitis plastica).
What are the histological features of gastric adenocarcinoma according to Lauren’s classification?
- Intestinal type: Tubular or glandular structure.
- Diffuse type: Signet ring cell appearance (the tumor cells accumulate intracellular mucin pushing the nucleus to the periphery), no glandular formation.
How does gastric cancer spread?
- Local spread to adjacent structures such as the pancreas and duodenum.
- Lymphatic spread to regional lymph nodes or distant lymph nodes (supraclavicular lymph nodes).
- Intraperitoneal spread and implanted in both ovaries (Krukenberg tumors).
- Hematogenous spread to the liver and lung.
What is gastric lymphoma, and what is its association with Helicobacter pylori?
• Gastric lymphoma accounts for 5% of all gastric malignancies and has a better prognosis.
• Helicobacter pylori has been associated with the development of extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma or MALTomas).
