title: Diagnosis of autoimmune pancreatitis by EUS-guided FNA using a 22-gauge needle: a prospective multicenter study.
abstract: OBJECTIVE
  Histopathologic examination is critical for diagnosing autoimmune pancreatitis (AIP). However, specimens obtained using EUS-guided FNA (EUS-FNA) are not recommended for histopathologic diagnosis because of inadequate sample size volume. We evaluated EUS-FNA efficacy for AIP diagnosis using a 22G needle.
  
  
  METHODS
  Seventy-eight patients exhibiting the imaging characteristics indicative of AIP in the pancreatic parenchyma and pancreatic duct underwent EUS-FNA with a 22G needle at 12 institutions between February 2013 and March 2014. Samples were evaluated for tissue sampling conditions, CD38- and IgG4-positive plasma cell counts, storiform fibrosis (SF), and obliterative phlebitis (OP).
  
  
  RESULTS
  Tissue specimens containing >10, 5 to 10, and 1 to 4 high-power fields (HPFs) were obtained from 29 (37.2%), 18 (23.1%), and 15 (19.2%) of 78 patients, respectively. The mean ± standard deviation (SD) CD38- and IgG4-positive plasma cell counts were 23.2 ± 18.8/HPF and 5.1 ± 6.7/HPF, respectively. SF was detected in 49 of 78 patients (62.8%) and OP in 38 of 78 patients (48.7%). According to the International Consensus Diagnostic Criteria (ICDC), histopathologic levels corresponded to level 1 in 32, level 2 in 13, and unclassifiable in 17 patients. Hence, 45 of 78 patients (57.7%) could be diagnosed with lymphoplasmacytic sclerosing pancreatitis according to ICDC.
  
  
  CONCLUSIONS
  Pancreatic tissues with at least 1 HPF were obtained by EUS-FNA from approximately 80% of patients, and nearly 60% of patients were diagnosed with ICDC level 2 or higher. Our findings indicate that EUS-FNA with a 22G needle may be useful for the histopathologic diagnosis of AIP. (Clinical trial registration number: UMIN000010097.).
authors.affiliation: Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kanno
authors.affiliation: Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Masamune
authors.affiliation: Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Fumiyoshi
authors.initials: F
authors.lastname: Fujishima
authors.affiliation: First Department of Internal Medicine, Gifu University Hospital, Gifu, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwashita
authors.affiliation: Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Kodama
authors.affiliation: Center for Gastroenterology, Teine-Keijinkai Hospital, Sapporo, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Katanuma
authors.affiliation: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ohara
authors.affiliation: Department of Gastroenterology and Hepatology, Kinki University Faculty of Medicine, Osaka, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kitano
authors.affiliation: Department of Gastroenterology and Hepatology, Mie University School of Medicine, Tsu, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Itoi
authors.affiliation: Department of Gastroenterology, Aichi Cancer Center Hospital, Nagoya, Japan.
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Mizuno
authors.affiliation: Department of Gastroenterology, Sapporo Kosei Hospital, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyakawa
authors.affiliation: Department of Gastroenterology and Nephrology, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Rintaro
authors.initials: R
authors.lastname: Mikata
authors.affiliation: Department of Gastroenterology, Fukushima Medical University Aizu Medical Center, Aizu-wakamatsu, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Irisawa
authors.affiliation: Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Sato
authors.affiliation: Department of Anatomic Pathology, Kurashiki Central Hospital, Kurashiki, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Notohara
authors.affiliation: Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Tooru
authors.initials: T
authors.lastname: Shimosegawa
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000032:analysis; D000368:Aged; D001327:Autoimmune Diseases / Q000150:complications / Q000175:diagnosis* / Q000473:pathology*; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000295:instrumentation*; D005260:Female; D005355:Fibrosis; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009339:Needles; D010179:Pancreas / Q000473:pathology*; D010195:Pancreatitis / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology*; D010950:Plasma Cells / Q000737:chemistry*; D011446:Prospective Studies
chemical_list: D007074:Immunoglobulin G; D051997:ADP-ribosyl Cyclase 1