title: Fine-needle aspiration cytology of intraductal papillary mucinous tumors of the pancreas.
abstract: BACKGROUND
  Intraductal papillary mucinous tumors (IPMT) account for 5% of pancreatic neoplasms. Preoperative identification is important because of their frequent multifocal or diffuse involvement in pancreatic ducts, which makes extensive surgery necessary even in benign cases. To the authors' knowledge, the cytologic features of this entity in fine-needle aspiration biopsy (FNAB) specimens have seldom been described and are poorly standardized.
  
  
  METHODS
  Eleven consecutive cases of surgically proven IPMT with previous endoscopic ultrasonography (EUS)-guided FNAB were collected for retrospective analysis. EUS-FNAB had been performed with on-site attendance of a cytopathologist in all cases. Macroscopic and microscopic appearance of mucin, cellular type and arrangement, presence of nuclear grooves, and degree of nuclear atypia were recorded.
  
  
  RESULTS
  Final diagnosis was benign IPMT (B) in four cases, borderline IPMT (Bo) in two cases, malignant IPMT (M) in one case, and IPMT associated with invasive carcinoma (Ca) in four. Retrospective analysis found moderate to high levels of extracellular mucin in 10 of the 11 cases. The other case (one Ca) showed a small amount of thick mucin. In all cases, epithelial cells were identified, although cellularity was very low in four cases (three B and one Bo). Atypia was absent in two cases (two B) slight in two cases (two B), moderate in three cases (one Bo and two Ca), and severe in four cases (one Bo, one M, and two Ca). Mucinous epithelium was found in nine cases and nonmucinous epithelium in five cases (one Bo and four Ca). Papillary structures were observed in five cases (two Bo and three Ca), sheets in eight cases (four B, one Bo, one M, and two Ca), single atypical cells in five cases (one Bo and four Ca), irregular clusters in three cases (one Bo and two Ca), and nuclear grooves in two cases (one B and one Bo).
  
  
  CONCLUSIONS
  The most common features of IPMT were extracellular mucin and sheets of mucinous epithelium. Papillae and nuclear grooves were not consistently found. Nonmucinous epithelium, severe atypia, single atypical cells, and irregular clusters indicated a high probability of malignant transformation. Even in the absence of atypia, a clinically significant diagnostic orientation can be established in most cases on the basis of the characteristic cytologic picture.
authors: Department of Pathology, Hospital Clínic, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain. manelsole@ub.edu
authors: Manel
authors: M
authors: Solé
authors: Carmela
authors: C
authors: Iglesias
authors: Glòria
authors: G
authors: Fernández-Esparrach
authors: Lluis
authors: L
authors: Colomo
authors: Maria
authors: M
authors: Pellisé
authors: Angels
authors: A
authors: Ginés
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis* / Q000473:pathology*; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000473:pathology*; D002471:Cell Transformation, Neoplastic; D003584:Cytological Techniques; D003937:Diagnosis, Differential; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000032:analysis; D012189:Retrospective Studies
chemical_list: D009077:Mucins