Pattern-based Histologic Approach in Very Early Onset IBD: Main Features and Differential Diagnosis

Area of Science:

• Pediatric Gastroenterology
• Gastrointestinal Pathology
• Immunology

Background:

• Very early onset inflammatory bowel disease (VEO-IBD) affects children under 6, encompassing classic IBD and monogenic disorders.
• VEO-IBD often presents with severe, treatment-resistant disease and a higher prevalence of genetic alterations compared to adult IBD.
• Histological findings in VEO-IBD can mimic classic IBD patterns or show unique features like apoptosis and enterocolitis, complicating diagnosis.

Purpose of the Study:

• To highlight the diagnostic complexities of VEO-IBD.
• To emphasize the differences in VEO-IBD histology compared to older patients.
• To advocate for a multidisciplinary, pattern-based histologic approach for accurate VEO-IBD diagnosis.

Main Methods:

• Review of VEO-IBD cases with a focus on gastrointestinal biopsy histology.
• Correlation of histological patterns with clinical presentation and laboratory findings.
• Analysis of diagnostic challenges and treatment implications.

Main Results:

• Histology in VEO-IBD can present as IBD-like, apoptotic, or enterocolitis-like patterns.
• Specific morphologic alterations (e.g., villous blunting, eosinophilic infiltrates) may suggest monogenic disorders.
• Monogenic VEO-IBD can involve primary immunodeficiency, impacting therapeutic strategies.

Conclusions:

• Accurate diagnosis of VEO-IBD is challenging due to overlapping histological features and disease heterogeneity.
• A pattern-based histologic approach, integrated with clinical and laboratory data, is essential for effective VEO-IBD management.
• Timely and precise diagnosis guides therapy, avoiding aggressive treatments and enabling targeted interventions for underlying defects.