A 38-year-old woman from Mumbai with a 6-week history of recurrent epigastric pain is found on upper GI endoscopy to have a 2 cm gastric ulcer on the lesser curvature. She denies NSAID use and H. pylori serology is negative. Which investigation is most appropriate to exclude a malignant lesion in this gastric ulcer?

## Investigation of Choice for Gastric Ulcer with Malignancy Concern **Key Point:** Endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) or tissue sampling is the most appropriate investigation to exclude malignancy in a gastric ulcer, especially when H. pylori is negative and NSAID use is excluded. ### Why EUS with Tissue Sampling? **High-Yield:** Gastric ulcers carry a risk of malignancy (gastric cancer masquerading as benign ulcer). When H. pylori and NSAIDs are excluded, malignancy must be ruled out. #### Advantages of EUS 1. **High spatial resolution:** Visualizes ulcer depth, wall layers, and surrounding tissues 2. **Tissue diagnosis:** FNA or fine-needle biopsy (FNB) provides histopathology 3. **Sensitivity for malignancy:** 85–95% for detecting gastric cancer 4. **Staging:** Assesses depth of invasion (T-staging) and regional lymph nodes (N-staging) 5. **Therapeutic capability:** Can perform tissue sampling in the same procedure ### Diagnostic Algorithm for Gastric Ulcer ```mermaid flowchart TD A[Gastric ulcer on endoscopy]:::outcome --> B{H. pylori positive?}:::decision B -->|Yes| C[Treat H. pylori]:::action B -->|No| D{NSAID use?}:::decision D -->|Yes| E[Stop NSAID + PPI]:::action D -->|No| F[Malignancy risk HIGH]:::urgent F --> G[EUS with FNA/FNB]:::action G --> H{Malignancy confirmed?}:::decision H -->|Yes| I[Surgical/oncologic management]:::action H -->|No| J[Benign ulcer - PPI therapy]:::action ``` ### When to Perform EUS in Gastric Ulcer | Scenario | Action | |---|---| | H. pylori positive, NSAID negative | Treat H. pylori; repeat endoscopy in 4–6 weeks | | NSAID positive, H. pylori negative | Stop NSAID; PPI therapy; repeat endoscopy in 4–6 weeks | | **H. pylori negative, NSAID negative** | **EUS with FNA/FNB (malignancy risk)** | | Ulcer with irregular margins, nodularity | EUS + tissue sampling | | Ulcer >3 cm or refractory to therapy | EUS + tissue sampling | **Clinical Pearl:** The lesser curvature location in this patient is a common site for gastric cancer. Combined with negative H. pylori serology and no NSAID use, malignancy must be excluded. ### Why Other Options Are Suboptimal #### Contrast-Enhanced CT Abdomen - Useful for **staging** confirmed gastric cancer (distant metastases, peritoneal involvement) - **NOT** a tissue diagnosis tool — cannot confirm malignancy - Lower sensitivity for small lesions or early gastric cancer - Better used after histologic confirmation #### Repeat Upper GI Endoscopy in 4 Weeks - Appropriate for H. pylori–positive or NSAID-related ulcers (to confirm healing) - **Inappropriate** when malignancy is suspected — delays diagnosis - Endoscopy alone cannot reliably distinguish benign from malignant ulcers on appearance - Tissue sampling is mandatory #### Serum CEA Level - **Not a diagnostic test** for gastric cancer - Used for **prognostication** and **follow-up** in confirmed gastric cancer - Low sensitivity and specificity for diagnosis - Elevated in many benign conditions (smoking, cirrhosis, inflammatory bowel disease) ### Mnemonic for Gastric Ulcer Aetiology **"CHAMP"** = **C**ancer (malignancy), **H**. pylori, **A**spirin/NSAIDs, **M**alignancy (stress ulcer), **P**ancreatic disease (ZES) **Tip:** In any gastric ulcer with negative H. pylori and no NSAID history, always think malignancy first and obtain tissue diagnosis via EUS-FNA. [cite:Harrison 21e Ch 297; Robbins 10e Ch 17]