title: EUS features of annular pancreas (with video).
abstract: BACKGROUND
  An annular pancreas is a rare congenital anomaly that results in a band of pancreatic tissue, either partially or completely encircling the duodenum.
  
  
  OBJECTIVE
  In patients referred for an upper-GI (UGI) EUS (1) to determine the prevalence of an annular pancreas identified by EUS versus CT and (2) to describe the EUS features of an annular pancreas.
  
  
  METHODS
  After review of UGI EUS procedures from January 1, 2000, through June 1, 2006, we conducted a retrospective review of EUS annular pancreas images to identify characteristic EUS features.
  
  
  METHODS
  This is the largest report describing the EUS findings in 5 patients.
  
  
  RESULTS
  Of 9776 patients undergoing UGI EUS, 5 patients (0.05%) (2 men; median age, 64 years; range, 44-69 years) were found to have an annular pancreas. EUS detected a band of pancreatic tissue that encircled the duodenum by 360 degrees (n = 3), 270 degrees (n = 1), or 180 degrees (n = 1). Within this band of tissue, the pancreatic duct was identified in 4 of 5 patients. The ductal and parenchymal features within the annular band were identical to those within the remaining pancreas in all patients. None of the patients had hypoechoic ventral anlage.
  
  
  CONCLUSIONS
  Whereas, firm EUS criteria of an annular pancreas cannot be established based on 5 patients, certain features may prove useful for diagnosis.
  
  
  CONCLUSIONS
  Although a diagnosis of an annular pancreas is rare, it should be considered in situations when a patient with possible associated symptoms has a normal CT.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
authors.forename: Georgios I
authors.initials: GI
authors.lastname: Papachristou
authors.forename: Mark D
authors.initials: MD
authors.lastname: Topazian
authors.forename: Ferga C
authors.initials: FC
authors.lastname: Gleeson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Levy
mesh_terms: D000328:Adult; D000368:Aged; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000151:congenital* / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014741:Video Recording