A 52-year-old man from rural India presents with a 6-month history of epigastric pain and melena. Upper endoscopy reveals a 1.5 cm ulcer on the lesser curve of the gastric antrum. Which is the most common site of peptic ulcer disease?

Explanation

## Most Common Site of Peptic Ulcer Disease ### Key Fact **High-Yield:** The **duodenal bulb (anterior wall)** is the most common site of peptic ulcer disease overall. Duodenal ulcers account for approximately **70–80%** of all peptic ulcers, with the vast majority located in the duodenal bulb (first part of the duodenum). This is a classic high-yield fact tested in NEET PG / INI-CET. ### Why the Duodenal Bulb? 1. **Acid exposure**: The duodenal bulb receives the highest concentration of gastric acid before it is neutralized by pancreatic bicarbonate 2. **H. pylori colonization**: *H. pylori* colonizes the gastric antrum and causes antral gastritis → increased gastrin → increased acid → duodenal mucosal injury (gastric metaplasia in duodenum → H. pylori colonization → ulceration) 3. **Anterior wall predominance**: The anterior wall of the duodenal bulb is the most common specific sub-site; posterior wall ulcers are associated with bleeding from the gastroduodenal artery ### Site Distribution in Peptic Ulcer Disease | Site | Frequency | Key Association | |------|-----------|----------------| | **Duodenal bulb (anterior wall)** | **~70–80% of all PUD** | H. pylori, most common overall | | Lesser curve of gastric antrum/prepyloric | ~15–20% of gastric ulcers | H. pylori | | Greater curve of gastric body | Less common | NSAIDs | | Fundus | Rare | NSAIDs, ZES | | Multiple / distal duodenum | Rare | Zollinger-Ellison Syndrome | *(Source: Robbins & Cotran Pathologic Basis of Disease, 10th ed., Chapter on GI Tract; Harrison's Principles of Internal Medicine, 21st ed.)* ### Clarifying the Distractor The lesser curve of the gastric antrum and prepyloric region (Option A) is the **most common site for gastric ulcers specifically**, accounting for ~60% of gastric ulcers. However, since duodenal ulcers are far more prevalent than gastric ulcers (ratio ~4:1), the duodenal bulb is the most common site of **peptic ulcer disease overall**. **Clinical Pearl:** The clinical vignette describes a gastric antral ulcer on the lesser curve — this is a classic H. pylori–associated gastric ulcer. However, the question asks for the most common site of PUD overall, which is the duodenal bulb. Always distinguish "most common gastric ulcer site" (lesser curve antrum) from "most common PUD site overall" (duodenal bulb). **Mnemonic:** **D**uodenal **B**ulb = **D**ominant site of **B**ulk of PUD cases.