RT Journal Article SR Electronic T1 Differential diagnosis between pancreatic neuroendocrine and solid pseudopapillary neoplasms on endoscopic ultrasound-guided fine-needle aspiration JF Saudi Medical Journal JO Saudi Med J FD Prince Sultan Military Medical City SP 744 OP 749 DO 10.15537/smj.2016.7.14212 VO 37 IS 7 A1 Raddaoui, Emad M. A1 Almadi, Majid A. A1 Aljebreen, Abdulrahman M. A1 Alsaif, Faisal A. A1 AlShedoukhy, Ahlam A. A1 Al-Lehibi, Abed H. A1 Almohameed, Khalid A. A1 Tsolakis, Apostolos V. A1 AlAbbadi, Mousa A. A1 Almutrafi, Amna R. YR 2016 UL http://smj.org.sa/content/37/7/744.abstract AB Objectives: 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.Conclusion: 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.