STEPTRACKERGASTROINTESTINAL | PATHOLOGY + ANATOMY | HIGH-YIELD REVIEW

Stomach II — Ulcers & Gastric Cancer

Peptic ulcers, the arteries they erode, the gastrinoma behind refractory ulcers — and two very different gastric adenocarcinomas.

FOCUS ON
Duodenal ulcers: pain better with food, almost always H pylori, almost never malignant. Gastric ulcers: pain worse with food, biopsy to exclude cancer. Posterior duodenal ulcer bleeds from the gastroduodenal artery; anterior ulcer perforates. Gastric cancer: intestinal (H pylori, diet) vs diffuse (signet ring, linitis plastica, CDH1).
DISORDER
MECHANISM · CAUSE
FEATURES
CLUE
Duodenal ulcer
↑ acid or ↓ bicarbonate; H pylori (~90%), NSAIDs, Zollinger-Ellison
Epigastric pain that improves with meals; may gain weight; first part of duodenum
Hypertrophy of Brunner glands · almost never malignant
Gastric ulcer
↓ mucosal protection; H pylori (~70%), NSAIDs, smoking
Pain worse with meals → weight loss; usually lesser curvature of antrum
Biopsy edges to exclude carcinoma
Ulcer hemorrhage
Erosion into an artery
Posterior duodenal wall → gastroduodenal a. · lesser curvature → left gastric a.
Most common complication
Ulcer perforation
Anterior duodenal ulcer through the full wall
Sudden severe pain, peritonitis, free air under the diaphragm, referred shoulder pain (phrenic irritation)
Posterior perforation → pancreatitis
Gastric outlet obstruction
Scarring/edema of pyloric channel or duodenum
Early satiety, vomiting of undigested food, succussion splash
Hypokalemic hypochloremic metabolic alkalosis
Zollinger-Ellison syndrome
Gastrinoma (duodenum or pancreas) → ↑↑ acid; 25% part of MEN1
Multiple, refractory ulcers, ulcers distal to the duodenal bulb (jejunum), diarrhea, steatorrhea (acid inactivates lipase)
↑ gastrin despite low gastric pH; ↑ gastrin after secretin
Intestinal-type gastric adenocarcinoma
H pylori, nitrosamines (smoked, salted foods — Japan), achlorhydria, chronic atrophic gastritis, blood type A
Gland-forming; large ulcer with heaped-up margins on lesser curvature
Follows metaplasia → dysplasia
Diffuse-type gastric adenocarcinoma
Loss of E-cadherin (CDH1); not linked to H pylori
Signet ring cells infiltrate the wall → thick rigid "leather bottle" (linitis plastica)
Hereditary diffuse gastric cancer → also lobular breast cancer
Gastric cancer spread
Lymphatic, peritoneal, hematogenous
Virchow node (left supraclavicular) · Sister Mary Joseph (umbilicus) · Krukenberg (bilateral ovaries, signet ring) · Blumer shelf · left axillary (Irish) node
Paraneoplastic: acanthosis nigricans, Leser-Trélat
GIST (stomach)
Interstitial cells of Cajal; KIT or PDGFRA mutation
Submucosal mass; stomach most common site
CD117 ⁺, DOG1 ⁺ · imatinib

Mechanism — aggression vs defense

AggressorsAcid, pepsin, H pylori, NSAIDs, smoking
⇄
DefensesMucus, HCO₃⁻, PGE₂, blood flow
→
UlcerThrough muscularis mucosae
Gastrinoma
→
Parietal cell hyperplasia↑↑ acid
→
Refractory ulcersJejunum
DiarrheaLipase inactivated

An erosion stays in the mucosa; an ulcer extends through the muscularis mucosae.

Gastric vs duodenal ulcer

FEATURE
GASTRIC
DUODENAL
Meals
Pain worse → weight loss
Pain better → weight gain
H pylori
~70%
~90%
Mechanism
↓ mucosal protection
↑ acid / ↓ HCO₃⁻
Malignancy
Possible — biopsy
Very rare
Bleeds from
Left gastric a.
Gastroduodenal a.

How it's tested

COMMON CONFUSIONIntestinal-type cancer forms glands and follows H pylori and diet. Diffuse-type has signet ring cells, CDH1 loss, a thick stiff wall and no clear link to H pylori.
THE TRAPA jejunal ulcer, or ulcers that come back after H pylori treatment, mean Zollinger-Ellison until proven otherwise. Check for MEN1 (calcium, prolactin).
YOUR APPROACHMeal relation → site → bleeding vessel or perforation → is it refractory (gastrinoma)? For a mass: gland-forming vs signet ring, and spread pattern.

If you see… think…

Epigastric pain relieved by eating → duodenal ulcer
Pain worse after meals with weight loss → gastric ulcer — biopsy
Massive bleed from a posterior duodenal ulcer → gastroduodenal artery
Sudden pain + free air under the diaphragm → perforated anterior duodenal ulcer
Multiple jejunal ulcers + diarrhea + ↑ gastrin after secretin → Zollinger-Ellison
Gastrinoma + hypercalcemia + pituitary tumor → MEN1
Signet ring cells + thick rigid stomach → diffuse adenocarcinoma (linitis plastica)
Bilateral ovarian masses with signet ring cells → Krukenberg tumor
Hard left supraclavicular node + weight loss → Virchow node (gastric cancer)
Submucosal gastric mass, CD117⁺ → GIST — imatinib