Peripancreatic Vascular Involvement in AIP: CGH | March 2026

Introduction

Autoimmune pancreatitis (AIP) is a unique IgG4-related inflammatory disease with generally favourable outcomes following glucocorticoid therapy. However, beyond pancreatic inflammation, extension into the peripancreatic vasculature can occur, leading to venous stenosis, collateral formation, and in severe cases, gastric varices. These vascular complications remain underrecognized and are not adequately addressed in existing diagnostic guidelines, despite their potential to cause life-threatening bleeding.

Problem Statement

There is limited large-scale evidence on the true prevalence, clinical significance, and treatment responsiveness of peripancreatic vascular involvement in AIP. Additionally, there is no clear strategy to identify patients at risk of gastric varices or variceal rupture, leading to potential missed opportunities for early intervention.

Summary

This multicenter Japanese study demonstrates that peripancreatic vascular involvement is common in AIP, occurring in over 50% of patients, most frequently affecting the splenic vein. Collateral formation was observed in 40%, and gastric varices were identified in approximately 11% of those undergoing endoscopy, with rare but serious cases of variceal rupture. Importantly, glucocorticoid therapy showed excellent efficacy, reversing venous stenosis in more than 90% of cases and improving collateral circulation in the majority. Severe splenic vein involvement emerged as a key predictor of gastric varices. These findings highlight the need for routine vascular assessment in AIP and selective endoscopic screening in high-risk patients to prevent fatal complications.