title: Rare pancreatic neoplasms: the utility of endoscopic ultrasound-guided fine-needle aspiration-a large single center study.
abstract: BACKGROUND
  Tumors other than ductal adenocarcinomas constitute 10%-15% of all pancreatic tumors. We describe the performance and pitfalls of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for diagnosis of these rare pancreatic tumors and their characteristic cytopathological features.
  
  
  METHODS
  The records of 455 pancreatic fine-needle aspiration procedures done between March 1997 and August 2006 at Aichi Cancer Center, Nagoya, Japan, were reviewed. Besides cytology, aspirated material was routinely submitted in formalin for cell-block analysis. The reference standard for final diagnosis was surgical pathology from resected specimens.
  
  
  RESULTS
  Twenty-eight rare (nonductal adenocarcinomas) pancreatic tumors were identified. Overall, EUS-FNA with the results of cytology, cell-block processing, and immunohistochemistry could correctly diagnose the type of neoplasm in 19 (67.9%) cases. EUS-FNA could distinguish benign from malignant rare tumors with a sensitivity of 69.2%, a specificity of 100%, positive predictive value of 100%, negative predictive value of 79.0%, and accuracy of 85.7%. None of three malignant pancreatic endocrine neoplasms could be diagnosed as malignant. An adequate core tissue sample could be obtained in 21 cases (75.0%) and provide a histopathological diagnosis in 19 (67.9%) cases. EUS-FNA could change the presumptive diagnosis in 11 (39.3%) cases. Specific immunochemical studies were useful adjuncts to the diagnosis. No major or minor complication was noted in any patient.
  
  
  CONCLUSIONS
  Pancreatic neoplasms other than ductal adenocarcinomas have diverse imaging and histopathological features. EUS-FNA is accurate and safe for their identification.
authors.affiliation: Department of Gastroenterology, Aichi Cancer Center Hospital, 1-1 Kanokoden Chikusa-ku, Nagoya 464-8681, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imaoka
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamao
authors.forename: Vikram
authors.initials: V
authors.lastname: Bhatia
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Koshikawa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D015331:Cohort Studies; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D035583:Rare Diseases; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome; D055815:Young Adult