Nishino Takayoshi    Department   School of Medicine(Yachiyo Medical Center), School of Medicine    Position   Professor
Article types	Original article
Language	English
Peer review	Non peer reviewed
Title	Guidance for diagnosing autoimmune pancreatitis with biopsy tissues.
Journal	Formal name：Pathology international Abbreviation：Pathol Int ISSN code：14401827/13205463
Domestic / Foregin	Foregin
Volume, Issue, Page	70(10),pp.699-711
Author and coauthor	Notohara Kenji, Kamisawa Terumi, Fukushima Noriyoshi, Furukawa Toru, Tajiri Takuma, Yamaguchi Hiroshi, Aishima Shinichi, Fukumura Yuki, Hirabayashi Kenichi, Iwasaki Eisuke, Kanno Atsushi, Kasashima Satomi, Kawashima Atsuhiro, Kojima Motohiro, Kubota Kensuke, Kuraishi Yasuhiro, Mitsuhashi Tomoko, Naito Yoshiki, Naitoh Itaru, Nakase Hiroshi, Nishino Takayoshi, Ohike Nobuyuki, Sakagami Junichi, Shimizu Kyoko, Shiokawa Masahiro, Uehara Takeshi, Ikeura Tsukasa, Kawa Shigeyuki, Okazaki Kazuichi
Publication date	2020/10
Summary	The biopsy-based diagnosis of autoimmune pancreatitis (AIP) is difficult but is becoming imperative for pathologists due to the increased amount of endoscopic ultrasound-guided biopsy tissue. To cope with this challenge, we propose guidance for the biopsy diagnosis of type 1 AIP. This guidance is for pathologists and comprises three main parts. The first part includes basic issues on tissue acquisition, staining, and final diagnosis, and is intended for gastroenterologists as well. The second part is a practical guide for diagnosing type 1 AIP based on the AIP clinical diagnostic criteria 2018. Inconsistent histological findings, tips for evaluating IgG4 immunostaining and key histological features including the ductal lesion and others are explained. Storiform fibrosis and obliterative phlebitis are diagnostic hallmarks but are sometimes equivocal. Storiform fibrosis is defined as spindle-shaped cells, inflammatory cells and fine collagen fibers forming a flowing arrangement. Obliterative phlebitis is defined as fibrous venous obliteration with inflammatory cells. Examples of each are provided. The third part describes the differentiation of AIP from pancreatic ductal adenocarcinoma (PDAC), focusing on histological features of acinar-ductal metaplasia in AIP, which is an important mimicker of PDAC. This guidance will help standardize pathology reports of pancreatic biopsies for diagnosing type 1 AIP.
DOI	10.1111/pin.12994
PMID	32767550