Endoscopic ultrasonography-guided fine needle aspiration biopsy using 22-gauge needle in diagnosis of autoimmune pancreatitis

Abstract

Backgrounds: The effectiveness of endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has not been fully evaluated in the diagnosis of autoimmune pancreatitis (AIP).

Aim: To evaluate the effectiveness of EUS-FNA using 22-gauge needles in the diagnosis of AIP.

Methods: EUS-FNA was examined in 85 patients with pancreatic mass, including 64 patients with pancreatic cancer and 21 patients with AIP. We investigated ability of EUS-FNA using 22-gauge needle for the differential diagnosis between AIP and pancreatic cancer. We also compared the factors concerning FNA procedures (number of needle passes, size of lesion, device, and amount of obtained pancreatic tissue) between two diseases.

Results: Tissues obtained from 21 patients with AIP, although none of them demonstrated histology suspicious for malignancy, did not show histological evidence definitive for AIP. The amount of obtained pancreatic tissue was almost equal between two diseases in each pancreatic location. Sensitivity, specificity, overall accuracy, and negative predictive value of histological diagnosis of pancreatic cancer were 92.2%, 100%, 94.1%, and 80.8%, respectively.

Conclusion: EUS-FNA using 22-gauge needle distinguished benign from malignant pancreatic mass with >90% of accuracy, regardless of the location. Hence, it was helpful for the clinical diagnosis of AIP, however not providing satisfactory samples for the histological diagnosis of AIP.