Gastric Cancer Types

Gastric Carcinoma

• Intestinal type: large, irregular ulcer with heaped up margins, commonly involves the lesser curvature of the antrum
• Risk factors: intestinal metaplasia (e.g., due to H pylori and autoimmune gastritis), nitrosamines in smoked foods (Japan), and blood type A
• Diffuse type: characterized by signet ring cells that diffusely infiltrate the gastric wall, resulting in thickening of the stomach wall (linitis plastica)
• Not associated with H pylori, intestinal metaplasia, or nitrosamines
• Presents late with weight loss, abdominal pain, anemia, and early satiety; rarely presents as acanthosis nigricans or Leser-Trelat sign
• Spread to lymph nodes can involve the left supraclavicular node (Virchow node)
• Distant metastasis most commonly involves the liver; other sites include the periumbilical region (Sister Mary Joseph nodule)

Peptic Ulcer Disease

• Solitary mucosal ulcer involving the proximal duodenum (90%) or distal stomach (10%)
• Duodenal ulcer: almost always due to H pylori (> 95%); rarely due to ZE syndrome
• Presents with epigastric pain that improves with meals
• Diagnostic endoscopic biopsy shows ulcer with hypertrophy of Brunner glands
• Usually arises in the anterior duodenum; when present in the posterior duodenum, rupture may lead to bleeding from the gastroduodenal artery or acute pancreatitis
• Gastric ulcer: usually due to H pylori (75%); other causes include NSAIDs and bile reflux
• Presents with epigastric pain that worsens with meals
• Ulcer is usually located on the lesser curvature of the antrum
• Rupture carries risk of bleeding from the left gastric artery
• Differential diagnosis of ulcers includes carcinoma
• Benign peptic ulcers are usually small (< 3 cm), sharply demarcated ("punched-out"), and surrounded by radiating folds of mucosa
• Malignant ulcers are large and irregular with heaped up margins
• Biopsy is required for definitive diagnosis

Acute Gastritis

• Acidic damage to the stomach mucosa
• Due to imbalance between mucosal defenses and acidic environment
• Defenses include mucin layer produced by foveolar cells, bicarbonate secretion by surface epithelium, and normal blood supply
• Risk factors: severe burn (Curling ulcer), NSAIDs, heavy alcohol consumption, chemotherapy, increased intracranial pressure (Cushing ulcer), and shock
• Acid damage results in superficial inflammation, erosion (loss of superficial epithelium), or ulcer (loss of mucosal layer)

Chronic Gastritis

• Chronic inflammation of the stomach mucosa