Endoscopic ultrasound-guided tissue acquisition for the histopathological diagnosis of autoimmune pancreatitis.

Autoimmune pancreatitis (AIP) is a disease concept that originated in Japan. It is characterized by diffuse pancreatic enlargement and irregular narrowing of the main pancreatic duct. Although the usefulness of the histological diagnosis of AIP using endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) and EUS-guided fine-needle biopsy (FNB) has been reported, enhanced diagnostic performance is expected with improvements in tissue collection methods and fine-needle techniques. Guidance for establishing the tissue diagnosis of AIP has been developed and is useful for histological evaluation. Histopathological diagnosis by EUS-FNA/FNB is expected to play a central role in AIP diagnosis in the future.