title: Fine needle aspirate of autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis): cytomorphologic characteristics and clinical correlates.
abstract: OBJECTIVE
  Autoimmune pancreatitis (AIP) is an inflammatory, IgG4-associated condition that often overlaps clinically and radiographically with pancreatic ductal adenocarcinoma. We reviewed our institutional experience with fine needle aspiration (FNA) cytology in patients subsequently diagnosed with AIP.
  
  
  METHODS
  A retrospective review was conducted of FNA results correlating to all surgical pancreatic specimens diagnosed as AIP or lymphoplasmacytic sclerosing pancreatitis from 1984 to 2011.
  
  
  RESULTS
  AIP was diagnosed in 15 cases by surgical resection and in 2 by combined clinical findings and nondiagnostic biopsies. Of 20 aspirates from 17 patients, 1 was diagnosed as malignant, 1 as neoplasm (mucinous), 10 as atypical, 5 as benign, and 3 as scant or nondiagnostic. Of the 10 aspirates diagnosed as atypical, 1 was suspicious for malignancy, 1 could not exclude neuroendocrine neoplasm, 1 was markedly atypical, and 7 demonstrated scattered ductal atypia. Common morphologic features included hypocellularity, focal-to-marked ductal epithelial atypia, fibrous tissue fragments, and a smear background lacking red blood cells.
  
  
  CONCLUSIONS
  On FNA, AIP most often leads to an 'atypical' cytopathologic interpretation and rarely may be diagnosed as adenocarcinoma. Thus, caution is warranted to avoid overdiagnosis on FNA when a mass lesion is reported in a patient with clinical or radiographic suspicion of AIP.
authors.affiliation: Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Brittany J
authors.initials: BJ
authors.lastname: Holmes
authors.forename: Ralph H
authors.initials: RH
authors.lastname: Hruban
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Wolfgang
authors.forename: Syed Z
authors.initials: SZ
authors.lastname: Ali
mesh_terms: D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000473:pathology*; D044963:Biopsy, Fine-Needle / Q000639:trends; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000473:pathology; D010195:Pancreatitis / Q000175:diagnosis / Q000473:pathology*; D012189:Retrospective Studies