title: Immature squamous metaplasia (focal atypical epithelial hyperplasia) of the pancreatic duct-immunohistochemical distinction from intraductal carcinoma.
abstract: OBJECTIVE
  Immature squamous metaplasia of the pancreatic duct (ISMPD) can be difficult to differentiate from an intraductal carcinoma of the pancreas (ICP), and little is known about the pathological nature of ISMPD. The aim of this study was to analyse 20 ISMPD and 10 ICP tissue samples.
  
  
  RESULTS
  ISMPD shares some characteristics with ICP. Seven of 20 ISMPD samples were covered by a layer of pancreatic duct epithelium, whereas this was not seen in the ICP samples. Immunohistochemistry of ISMPD revealed positivity for p63 (100%), cytokeratin 5/6 (95%), cytokeratin 7 (95%), cytokeratin 20 (10%), and MUC-1 (95%), and the samples were negative for p53, carcinoembryonic antigen (CEA), and bcl-2. In contrast, ICP was positive for p63 (40%), p53 (10%), cytokeratin 7 (90%), cytokeratin 20 (20%), CEA (30%), and MUC-1 (80%), and negative for cytokeratin 5/6. However, in 84% (16) of the ISMPD samples, cytokeratin 7 was expressed only by an epithelial layer at the apical surface; this expression pattern was not found in any of the 10 ICP samples. The mean Ki67 labelling index was 1.0% in ISMPD and 18.5% in ICP.
  
  
  CONCLUSIONS
  Our study suggests that immunohistochemical staining for cytokeratin 5/6 and Ki67 constitutes the best combination for differentiating ISMPD from ICP.
authors.affiliation: Department of Pathology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Mochizuki
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kondo
authors.forename: Naoki
authors.initials: N
authors.lastname: Oishi
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Tadao
authors.initials: T
authors.lastname: Nakazawa
authors.forename: Tetsu
authors.initials: T
authors.lastname: Yamane
authors.forename: Ryohei
authors.initials: R
authors.lastname: Katoh
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D018396:Mucin-1 / Q000378:metabolism; D010183:Pancreatic Ducts / Q000378:metabolism* / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D014157:Transcription Factors / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; C060192:MUC1 protein, human; D018396:Mucin-1; C115051:TP63 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D007633:Keratins
keywords: PanIN-3; immunohistochemistry; intraductal carcinoma; pancreas; squamous metaplasia