## Barrett's Esophagus: Metaplasia and Dysplasia Assessment **Key Point:** The salmon-pink patch represents Barrett's esophagus (columnar metaplasia of the esophagus). Histopathological assessment with dysplasia grading is essential to stratify malignant transformation risk. ### Understanding Barrett's Esophagus **Definition:** Replacement of normal stratified squamous epithelium of the distal esophagus with columnar epithelium (metaplasia), typically intestinal-type with goblet cells. **Pathogenesis:** 1. Chronic GERD causes repeated acid injury 2. Squamous epithelium is replaced by columnar epithelium (metaplasia) 3. Accumulation of mutations leads to dysplasia 4. Risk of progression to adenocarcinoma ### Why Endoscopic Biopsy with Dysplasia Grading is Correct **High-Yield:** Dysplasia grade is the strongest predictor of malignant transformation risk: | Dysplasia Grade | Annual Cancer Risk | Management | |---|---|---| | No dysplasia | 0.2–0.5% | Surveillance endoscopy q 3–5 years | | Indefinite for dysplasia | 0.5–1% | Repeat biopsy in 3–6 months | | Low-grade dysplasia (LGD) | 0.5–0.7% | Surveillance or endoscopic therapy | | High-grade dysplasia (HGD) | 5–7% | Endoscopic ablation/resection | | Intramucosal carcinoma | >30% | Endoscopic resection or surgery | **Clinical Pearl:** Multiple biopsies (4-quadrant sampling every 1–2 cm) are recommended because dysplasia may be patchy and multifocal. A single biopsy may miss dysplasia in up to 40% of cases. ### Histological Features of Dysplasia in Barrett's **Low-Grade Dysplasia:** - Nuclear enlargement and hyperchromasia - Increased nuclear-to-cytoplasmic ratio - Intact basement membrane - Preserved mucosal architecture **High-Grade Dysplasia:** - Marked nuclear abnormalities - Loss of mucosal architecture - Increased mitotic figures - Intact basement membrane (distinguishes from intramucosal carcinoma) **Mnemonic:** **NDHI** — Nuclear enlargement, Dysplasia grading, Hyperchromasia, Intact basement membrane (features of dysplasia in Barrett's). ### Why Other Investigations Are Inadequate | Investigation | Role | Why Not First-Line | |---|---|---| | Endoscopic biopsy + histology | **Gold standard** — diagnoses metaplasia and grades dysplasia | — | | Esophageal manometry | Assesses motility; used for dysphagia evaluation | Does not assess dysplasia or malignant transformation risk | | 24-hour pH monitoring | Confirms GERD; guides medical management | Does not assess Barrett's dysplasia or cancer risk | | EUS alone | Assesses wall layers and lymph nodes; useful for staging | Cannot diagnose dysplasia; requires tissue sampling | **Warning:** Do not confuse metaplasia (Barrett's esophagus) with dysplasia. Barrett's is the metaplastic change; dysplasia is the premalignant progression within Barrett's. Both require histology to confirm. **Tip:** In clinical practice, if HGD is found, confirm with a second pathologist and proceed to endoscopic therapy (radiofrequency ablation or endoscopic mucosal resection) because the risk of occult invasive carcinoma is 30–40%. [cite:Robbins 10e Ch 17]
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