title: Differential diagnosis between pancreatic neuroendocrine and solid pseudopapillary neoplasms on endoscopic ultrasound-guided fine-needle aspiration. An immunohistochemical study.
abstract: OBJECTIVE
  To evaluate the role of applying a limited panel of immunohistochemical stains on the cellblock preparation from samples obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the aim of differentiating solid pseudopapillary neoplasms (SPNs) from neuroendocrine tumors (NETs).
  
  
  METHODS
  We retrospectively retrieved all the EUS-FNAs of the pancreas that have a diagnosis of NET or SPN that were performed at 2 tertiary care hospitals in Riyadh, Kingdom of Saudi Arabia from May 2004 to December 2014. Diff-Quik, Papanicolaou, and Immunohistochemistry stains on cellblock preparations were performed.
  
  
  RESULTS
  Twenty cases were available (16 pancreatic neuroendocrine tumors (pNETs) and 4 SPNs). The pNETs were immunoreactive for synaptophysin, chromogranin A and CD56 while E-cadherin was diffusely to focally cytoplasmic positive. β-catenin was negative or showed focal cytoplasmic immunoreactivity. In comparison, SPNs were positive for vimentin, CD10, CD-56, focally positive for progesterone receptors and synaptophysin, and revealed nuclear immunostaining for β-catenin. They were negative for chromogranin A and E-cadherin.
  
  
  CONCLUSIONS
  Based on EUS-FNA samples, nuclear immunoreactivity for β-catenin with loss of membranous immunostaining for E-Cadherin can potentially facilitate differentiating SPNs from pNETs.
authors.affiliation: Department of Pathology, College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia. E-mail. bmujahid@gmail.com.
authors.forename: Emad M
authors.initials: EM
authors.lastname: Raddaoui
authors.forename: Majid A
authors.initials: MA
authors.lastname: Almadi
authors.forename: Abdulrahman M
authors.initials: AM
authors.lastname: Aljebreen
authors.forename: Faisal A
authors.initials: FA
authors.lastname: Alsaif
authors.forename: Ahlam A
authors.initials: AA
authors.lastname: AlShedoukhy
authors.forename: Abed H
authors.initials: AH
authors.lastname: Al-Lehibi
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Almohameed
authors.forename: Apostolos V
authors.initials: AV
authors.lastname: Tsolakis
authors.forename: Mousa A
authors.initials: MA
authors.lastname: AlAbbadi
authors.forename: Amna R
authors.initials: AR
authors.lastname: Almutrafi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D003937:Diagnosis, Differential; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000473:pathology