Fine-Needle Aspiration Cytology in the Diagnosis of Pancreatic Neuroendocrine Tumors: A Single-Center Experience of 25 Cases.

Pancreatic neuroendocrine tumors (Pan NETs) are rare but are being increasingly diagnosed. The objective of this retrospective study was to share our experience of fine-needle aspiration (FNA), including endoscopic ultrasound-guided FNA with rapid on-site evaluation (ROSE), with the use of immunohistochemical (IHC) markers in the diagnosis of Pan NET.A total of 25 cases of Pan NET diagnosed on pancreatic FNA between 2008 and 2013 were identified from our hospital database. Clinical history, radiology, cytomorphological features, and IHC performed were reviewed.The mean age of our patient group was 52 years; 15/25 were male. Most presented with abdominal pain and the majority of the lesions were in the pancreatic body, the largest being 14 cm in size. Based on the 2010 World Health Organization criteria, cases were further graded as follows: 21 cases were grade 1, 2 cases were grade 2 and 2 cases were grade 3. Proliferation marker Ki-67 was utilized in 6 cases for definitive grading. Of the 25 cases, 23 were diagnosed as nonfunctional while 2 were functional; 1 patient had MEN-1 syndrome and 1 had von Recklinghausen's syndrome.Our data suggests that FNA, with ROSE and IHC markers, is highly sensitive and specific for diagnosing Pan NET.