Introduction to Pancreatic Pathology and Fine-Needle Aspiration Cytology.

This introductory chapter discusses the demographics of pancreatic tumors and the risk factors associated with pancreatic neoplasms. The WHO 2019 classification of pancreatic epithelial tumors and WHO 2017 classification of pancreatic neuroendocrine neoplasms is provided. The current role of fine-needle aspiration (FNA) in the pancreatic lesions, different radiographic modalities and their evolution in the FNA of pancreatic lesions, and utility of rapid on-site evaluation of pancreatic cytology is also discussed. Guidelines on pancreatic pathology provided by the Papanicolaou Society of Cytopathology (PSC) in 2014 are summarized. These guidelines, which are provided by experts in the field, establish recommendations for clinical follow-up, indications, and preprocedural studies for pancreatic FNA, different techniques of pancreatic FNA, postprocedural follow-up, treatment options for different pancreatobiliary lesions, and utilization of ancillary studies for cytological diagnosis of pancreatic lesions. Standardization of the terminology and nomenclature and the diagnostic categories provided by the PSC are also discussed. Lastly, an algorithmic approach to cytological evaluation of pancreatic masses is provided.