Journal Article

Type 1 autoimmune pancreatitis: clinical features and independent predictors of histopathological confirmation via EUS-guided fine-needle aspiration/fine-needle biopsy

Liu, Chao, Jin, Zhendong, Wan, Dongling, Li, Jiayu, Cui, Hanxiao, Yang, Zhenghui, Li, Wanshun, Sun, Liqi, Jiang, Mengruo, Tian, Xiaorong, Zhang, Deyu, Huang, Haojie, Zhou, Yuyan, Xu, Jiaheng

2026

Overview

Background In diagnosing type 1 autoimmune pancreatitis (AIP), serum IgG4 (sIgG4) can be false-negative. EUS-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) pathology is key for diagnosis, but clinical features’ impact on pathologic confirmation is unclear. This study analyzed their link and factors improve diagnostic accuracy. Methods We analyzed data from a single-center retrospective study at Changhai Hospital (Jan 2009-Jan 2024). Type 1 AIP was diagnosed per International Consensus Diagnostic Criteria (ICDC). Patients with surgical diagnosis, no EUS, or incomplete biopsy data were excluded; eligible cases were grouped into “Confirmed”/“Unconfirmed” per ICDC. Baseline data, laboratory indicators, imaging, and EUS-FNA/FNB data were collected. Statistical analyses (ROC, χ² tests, multivariate logistic regression) were done with R 4.4.0. Results A total of 182 suspected type 1 AIP patients were enrolled; 84.07% were male, 88.46% middle-aged/elderly. Common symptoms: abdominal discomfort (65.93%), obstructive jaundice (43.41%). sIgG4 > 2×ULN (twice upper normal limit) occurred in 64.84%. Multivariate analysis: pathological confirmation rate 65.12% (EUS-FNB) vs. 18.75% (EUS-FNA) ( P  < .001, former higher). For IgG4-positive cells: 82.56% confirmation rate (> 10 cells/high-power field[HPF]) vs. 16.67% (< 10 cells/HPF) ( P  < .001). EUS-FNB (OR = 3.56, 95% CI: 1.55–8.18, P  = .003) and IgG4-positive cell count (> 10 cells/HPF) (OR = 15.71, 95% CI: 6.96–35.46, P  < .001) were independent confirmation predictors. Gender, age, sIgG4 had limited value; renal involvement, retroperitoneal fibrosis were auxiliary indicators. Conclusions Following systematic multi-dimensional factor screening, pathological confirmation of type 1 AIP relies on two key factors: EUS-FNB and histopathological detection of IgG4-positive cells (> 10 cells/HPF). Integrating these core diagnostic modalities with additional indicators—such as auxiliary markers of extrapancreatic involvement (e.g., renal involvement)—further enhances diagnostic precision, which facilitates the refinement of clinical diagnostic workflows for type 1 AIP.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Autoimmune diseases / B cells / Biopsy / Biopsy, Needle / Development and progression / Diabetes / Diagnosis / Diagnostic accuracy / Diagnostic equipment (Medical) / Disease / Endoscopic ultrasonography / EUS-guided fine-needle biopsy (EUS-FNB) / Families & family life / Family medical history / Fibrosis / Gastroenterology / Hepatology / Histology, Pathological / Histopathology / Hospitals / Hypertension / IgG4-positive cell count / Immunoglobulin G / Internal Medicine / Jaundice / Laboratories / Magnetic resonance imaging / Medical research / Medicine / Medicine & Public Health / Medicine, Experimental / Methods / Multivariate analysis / Pancreatitis / Pathology / Patients / Physiological aspects / Smoking / Statistical analysis / Steroids / Type 1 autoimmune pancreatitis (type 1 AIP)