Pathology of the Stomach Flashcards
Anatomic landmarks of stomach
- cardia
- fundus
- body
- antrum
- pylorus
Characteristics of gastric mucosal barrier
- surface mucus secretion
- bicarbonate secretion into mucus
- epithelium = performs barrier fxn
- good regenerative capacity
- elaboration of prostaglandins
Adult vs. Juvenile pyloric stenosis
- infantile (congenital)
- hyperplasia of pyloric muscularis propria ==> obstruction of gastric outflow
- presents 2nd-3rd week of life (M>>F)
- regurg + projectile vomiting
- firm ovoid abdominal mass
- adult (aquired)
- consequence of antral gastritis or peptic ulcers close to pylorus
Gastritis vs. Gastropathy
- Gastritis = Mucosal inflammatory process
- Gastropathy = Mucosal changes without much inflammation.
Causes of acute gastritis
- **H. pylori
- ** NSAIDs, drugs
- stress-related ulcers
- alcohol, diet
- chemical ingestion
Features?
- dx: small gastric ulceration (acute gastritis)
- features
- acute inflammation (PMNs)
- erosion of epithelium
Most common causes of chronic gastritis
1) ***Helicobacter pylori*** - antrum
2) Autoimmune gastritis (less than 10% of cases of chronic gastritis) - body
Histologic features of H. pylori chronic gastritis
- H. pylori stain
- usually acute on chronic gastritic changes
- lymphs and plasma cells @ lamina propria
- lymphoid aggregate w/germinal center
Peptic Ucler Disease definition
- Disease characterized by peptic ulcers
- peptic ulcer = distinct breach in the mucosal lining of the esophagus (esophageal ulcer), stomach (gastric ulcer) or the first part of the small intestine (duodenal ulcer)
- ulcers result from caustic effects of acid and pepsin in the lumen
Risk factors for development of PUD
- H.pylori infection → compromise mucosal defense → gastric hyperacidity → mucosal damage and ulceration
- NSAID use → direct chemical irritation + suppression of prostaglandin synthesis
- Cigarettes → impairs mucosal blood flow and healing
Diseases associated w/H. pylori infection
- ) Acute and chronic gastritis
- ) Gastric and duodenal ulcers (PUD)
- ) Gastric adenocarcinoma
- ) MALT Lymphoma (mucosa associated lymphoid tissue)
Characteristics of autoimmune chronic gastritis
- <10% of chronic gastritis
- SPARES antrum; mostly occurs @ BODY
- ==> destruction of parietal cells
- decreased acid + elevated gastrin
- pernicious anemia (decreased IF)
Most common types of stomach polyps
- hyperplastic polyp
- antrum > body
- H. pylori associated
- polypoid gastritis
- antrum > body
- H. pylori associated
- adenoma
- antrum > body
- solitary, malignant precursor
Characteristics of hyperplastic polyps
- Inflammatory polyp, arise in association with chronic gastritis
- Exaggerated mucosal response to injury and inflammation
- cellular origin: Foveolar epithelium and lamina propria
Characteristics of gastric adenomas
- Adenomas exhibit dysplasia and are precursors to adenocarcinoma (malignancy)
- Arise in a background of chronic gastritis with atrophy and intestinal metaplasia
- cellular origin: dysplasia of lining epithelial cells
- Evolution of an Adenoma:
- Chronic gastritis ==> intestinal metaplasia ==> low-grade dysplasia/”adenoma” ==> high-grade dysplasia ==> invasive adenocarcinoma
Common types of gastric tumors
- Adenocarcinoma
- Gastrointestinal Stromal Tumors (GIST)
- Neuroendocrine tumors (carcinoid)
- Lymphoma (MALT)
- Metastatic tumors
- Melanoma
- Breast
Characteristics of gastric adenocarcinoma
- Epithelial tumor derived from malignant transformation of the gastric epithelium (precursor lesion = adenoma)
- Subtypes
- Intestinal type – tends to form masses
- Diffuse type – diffusely infiltrative
Risk factors: Intestinal Adenocarcinoma vs. Diffuse Adenocarcinoma
- Both: Chronic gastritis, H.pylori infection
- Intestinal type:
- Tobacco
- diet (smoked foods, salted fish/meat, pickled vegetables)
- inherited cancer syndromes
- Diffuse type:
- Mutations in CDH1 (Hereditary Diffuse Gastric Cancer)
Gross findings: Intestinal Adenocarcinoma vs. Diffuse-type Adenocarcinoma
- Intestinal type: Ulcer with heaped-up borders
- Diffuse type: “Linitis plastica” thickened wall with loss of rugal folds, leather bottle
Histologic features: Intestinal vs. Diffuse-type adenocarcinoma
- intestinal = glandular, fibrosis
- diffuse type = signet ring cells
Characteristics of GI Stromal Tumors (GIST)
- clinical
- older pt/s
- weight loss, anemia, dyspepsia
- pathogenesis
- Stromal tumor derived from the Interstitial Cells of Cajal
- ICC = pacemaker cells for gut peristalsis @ muscularis propria
- 80% are due to an activating mutation in the gene encoding the tyrosine kinase CKIT
- KIT negative GIST: Majority are gastric/extraintestinal: PDGFRA mutated
- Stromal tumor derived from the Interstitial Cells of Cajal
