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The following is a summary of “Impact of EUS-guided fine-needle biopsy on International Consensus Diagnostic Criteria for Diagnosing Autoimmune Pancreatitis: a prospective multicenter study,” published in the February 2025 issue of the Gastrointestinal Endoscopy by Bellocchi et al.

The histological diagnosis of autoimmune pancreatitis (AIP) remains a significant challenge, particularly in the preoperative setting. The advent of new-generation “end-cutting” needles has demonstrated promising results in improving diagnostic accuracy. This study aimed to evaluate the effectiveness of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) in enhancing the diagnostic classification of AIP based on the International Consensus Diagnostic Criteria (ICDC) and in determining specific AIP subtypes.

A multicenter, prospective study was conducted across four centers, enrolling adult patients with suspected AIP. Patients with a definitive AIP diagnosis according to ICDC or those who had recently undergone steroid treatment were excluded. All procedures utilized a 22-gauge end-cutting needle. The primary objective was to assess the rate at which EUS-FNB improved ICDC classification levels. Secondary objectives included evaluating the proportion of patients classified under level 1 or 2 histological criteria, determining the diagnostic accuracy of EUS-FNB, identifying malignancies, and assessing procedural safety.

A total of 52 patients (75% male, mean age 57.9 ± 17.3 years) with either focal (n=50) or diffuse (n=2) pancreatic lesions were enrolled. Final diagnoses included AIP in 39 patients (75%), chronic pancreatitis in 6 patients (11.5%), and malignancy in 7 patients (13.5%). EUS-FNB significantly improved the diagnostic classification of AIP in 92.3% of cases, with 74.3% achieving definitive diagnosis and 17.9% classified as probable AIP. Histological findings compatible with level 1 ICDC criteria were identified in 73.1% of type 1 AIP cases and 50% of type 2 AIP cases, while level 2 criteria were met in 23.1% and 41.7%, respectively. The overall diagnostic accuracy of EUS-FNB was 94.2% (95% CI: 84.1–98.8). Importantly, EUS-FNB facilitated malignancy exclusion in patients presenting with focal pancreatic lesions. The procedure demonstrated a favorable safety profile, with only two cases (3.8%) of mild post-procedural pancreatitis.

In conclusion, EUS-FNB utilizing end-cutting needles significantly enhances the histological classification of AIP, leading to an improvement in ICDC-based diagnostic accuracy in over 90% of cases. Furthermore, this approach effectively differentiates AIP from malignancy in patients with focal pancreatic lesions and provides valuable subtype characterization. These findings highlight the potential of EUS-FNB as a critical tool in the diagnostic pathway for AIP, reducing diagnostic uncertainty and guiding clinical management. Further studies are warranted to refine procedural protocols and validate these findings in larger patient populations.

Source: giejournal.org/article/S0016-5107(25)00140-3/abstract