How is Barrett's esophagus classified?

Classifications of Barrett's Esophagus

Barrett's esophagus is classified based on three key systems: segment length (using Prague C&M criteria), histopathological type (presence or absence of intestinal metaplasia), and degree of dysplasia (non-dysplastic, low-grade, high-grade, or intramucosal carcinoma). 1

Endoscopic Length Classification (Prague C&M System)

The Prague classification is the standardized method for documenting Barrett's extent and must be used in all cases 1, 2:

• C (Circumferential extent): Length in centimeters of circumferential columnar lining above the gastroesophageal junction 2
• M (Maximum extent): Maximum length in centimeters of any tongues of columnar epithelium extending above the gastroesophageal junction 2
• Minimum diagnostic threshold: At least 1 cm of columnar epithelium must be clearly visible above the gastroesophageal junction for an endoscopic diagnosis 1, 2

Traditional Length-Based Categories

While the Prague system is preferred, Barrett's is historically divided by segment length 1, 3:

• Long-segment Barrett's esophagus (LSBO): Typically ≥3 cm of columnar-lined epithelium 1
• Short-segment Barrett's esophagus (SSBO): <3 cm of columnar-lined epithelium 1, 3
• Clinical significance: Longer segments carry higher cancer risk, with each 1 cm increase associated with a 1.17-fold increased odds of high-grade dysplasia or adenocarcinoma 1

Important caveat: An irregular Z-line with tongues <1 cm should NOT be diagnosed as Barrett's esophagus 1, 2. This distinction is critical to avoid overdiagnosis.

Histopathological Classification

Barrett's is classified by epithelial type present on biopsy 1:

By Metaplastic Type

• Barrett's with intestinal metaplasia: Contains specialized columnar epithelium with acid mucin-containing goblet cells 1, 4

  • This is the most biologically unstable type with highest cancer risk 1
  • Annual incidence of high-grade dysplasia/cancer is 0.38% with intestinal metaplasia vs 0.07% without 1
  • Subtypes include incomplete (type II or III) with mucous and goblet cells, or complete (type I) with absorptive cells 1

• Barrett's with gastric metaplasia only: Contains gastric fundal-type or junctional-type epithelium without goblet cells 1

  • The British Society of Gastroenterology recognizes this as Barrett's, though it carries lower cancer risk 1
  • NICE guidelines acknowledge higher cancer risk when intestinal metaplasia is present 1

Key controversy: Some societies (particularly American) require intestinal metaplasia for diagnosis, while British guidelines accept gastric metaplasia alone 1. In practice, only intestinal metaplasia has established cancer risk, making this distinction clinically important for risk stratification 1.

Dysplasia Classification

This is the most critical classification for management decisions 1, 4, 5:

• Non-dysplastic Barrett's esophagus (NDBO): No dysplastic changes present 1
• Indefinite for dysplasia: Epithelial changes present but cannot definitively distinguish regenerative changes from true dysplasia 1, 5
• Low-grade dysplasia (LGD): Neoplastic epithelial changes confined to lower half of crypts 1, 5
• High-grade dysplasia (HGD): Neoplastic changes involving full thickness of epithelium 1, 5
• Intramucosal carcinoma: Malignant cells invading lamina propria but not through muscularis mucosae 1, 5

Critical pitfall: Dysplasia diagnosis has significant interobserver variability, particularly distinguishing indefinite from low-grade dysplasia 1, 5. All dysplasia diagnoses must be confirmed by an expert gastrointestinal pathologist before treatment decisions 1.

Dysplasia Recognition Challenges

Active inflammation from ongoing reflux can mimic dysplasia, creating regenerative epithelial atypia that mimics high-grade dysplasia 1, 5. Biopsies should ideally not be performed in the presence of erosive esophagitis (Los Angeles grade C or D), and if dysplasia is suggested, repeat biopsies after intensified acid suppression are mandatory 1.

Diagnostic Requirements

A definitive Barrett's diagnosis requires synthesis of both endoscopic and histopathological findings 1:

• Endoscopic: ≥1 cm columnar epithelium above gastroesophageal junction using Prague criteria 1, 2
• Histologic: Columnar metaplasia (with or without intestinal metaplasia depending on guideline) on four-quadrant biopsies every 2 cm (Seattle protocol) 1
• Native structures: Presence of submucosal esophageal glands or ducts confirms esophageal origin, but these are only seen in 10-15% of biopsies 1