title: EUS findings in patients with autoimmune pancreatitis.
abstract: BACKGROUND
  Autoimmune pancreatitis is an increasingly recognized benign condition with a presentation similar to pancreatic neoplasia but responds to corticosteroid therapy. Clinical features, ERCP, and CT findings have been described. This study assessed the EUS and EUS-guided FNA features of proven autoimmune pancreatitis.
  
  
  METHODS
  The diagnosis of autoimmune pancreatitis was based on examination of surgical resection specimens or typical clinical findings (elevated immunoglobulin G level, no evidence of malignancy, characteristic non-EUS imaging studies, and clinical improvement, especially in response to treatment with a corticosteroid).
  
  
  RESULTS
  Presenting manifestations in 14 patients included obstructive jaundice, abdominal pain, and weight loss. Ten patients underwent surgery (including exploratory surgery). Six were successfully treated with corticosteroid. EUS revealed diffuse hypoechoic pancreatic enlargement (8/14) or a focal irregular hypoechoic mass (6/14). Features of chronic pancreatitis were not noted. EUS-guided FNA of the pancreas was suggestive of chronic inflammatory pancreatitis in 9 of 12 patients. Celiac and peripancreatic lymphadenopathy (up to 3 cm in diameter) was present in 6 patients. EUS-guided FNA of lymph nodes (3/4) did not reveal evidence of malignancy. Vascular involvement was noted in 3 patients.
  
  
  CONCLUSIONS
  The EUS features of autoimmune pancreatitis are easily mistaken for malignancy. However, a diffusely hypoechoic, enlarged pancreas, together with chronic inflammatory cells in aspirated cytologic specimens, is supportive of the diagnosis of autoimmune pancreatitis. When combined with clinical data, EUS and EUS-guided FNA may support a diagnosis of autoimmune pancreatitis, may warrant a trial of corticosteroid, and thereby may prevent unnecessary surgery.
authors.affiliation: Division of Digestive Diseases, School of Medicine, UCLA Center for the Health Sciences, University of California-Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Farrell
authors.forename: John
authors.initials: J
authors.lastname: Garber
authors.forename: Dushyant
authors.initials: D
authors.lastname: Sahani
authors.forename: William R
authors.initials: WR
authors.lastname: Brugge
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D044963:Biopsy, Fine-Needle; D019160:Endosonography; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging / Q000473:pathology; D010195:Pancreatitis / Q000000981:diagnostic imaging / Q000473:pathology*; D010950:Plasma Cells / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D005719:gamma-Globulins / Q000378:metabolism
chemical_list: D007074:Immunoglobulin G; D005719:gamma-Globulins