Vienna Classification • Barrett's Dysplasia Rubric
Pathological Category
Select the pathological category from the biopsy report to visualize the Vienna classification management profile.
Guidelines & Evidence
Verified
Last Review: 2026
When to Use
When to Use
Historical phenotypic characterization of Crohn's disease
Interpreting older clinical trial data (pre-2005) where "ALB" was first defined
Baseline classification for long-term longitudinal research studies
Supersession Note
The Vienna Classification (1998) was updated and largely replaced by the Montreal Classification (2005). Use the Montreal version for modern clinical registries.
How it Works
A: Age at Diagnosis
| A1 | < 40 years |
| A2 | ≥ 40 years |
L: Disease Location
| L1 | Terminal Ileum |
| L2 | Colon |
| L3 | Ileocolon |
| L4 | Upper GI tract |
B: Disease Behavior
| B1 | Non-stricturing, non-penetrating |
| B2 | Stricturing |
| B3 | Penetrating (Fistulae or abscess) |
Clinical Pearls
Why it was Updated
The Vienna system lacked a distinction for pediatric onset (now Montreal A1) and didn't allow for the "Upper GI" modifier (L4) to coexist with other locations. It also failed to correctly categorize "Perianal disease," which is now considered a modifier in the Montreal system.
Clinical Pearls
Vienna was the first global attempt to move beyond just "Small vs. Large bowel" descriptions
Behavior (B2/B3) remains the strongest predictor for the lifetime risk of surgical resection
Age < 40 (A1) was found to be the demographic most likely to present with extensive L3 disease
Next Steps
Recommendation
01
Transition to Montreal: Recalculate phenotype using Montreal criteria for better prognostic accuracy.
The Evidence
The Foundational System
A simple classification of Crohn's disease: report of the Working Party for the World Congresses of Gastroenterology, Vienna 1998.
Gasche C et al. • Inflammatory Bowel Diseases. 2000;6(1):8-15. The consensus document that started standardized phenotypic coding.
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Origins & History
Vienna World Congress
Convened by Christoph Gasche and colleagues. Before Vienna, Crohn's descriptions were a "Babel" of different terms. This was the first attempt at a global semantic taxonomy for the disease.
Last Comprehensive Review: 2026