Pancreatic pathology: an update

Pancreatic ductal adenocarcinoma (PDAC) takes centre stage in the field of pancreatic pathology. It is the most common pancreatic neoplasm and carries a dismal prognosis with rising mortality rates. Tissue diagnosis focuses on the identification of PDAC and its distinction from non-neoplastic disorders such as chronic pancreatitis and rarer, less aggressive pancreatic neoplasms. Pathology also plays a key role in the assessment of well characterized macroscopic precursor lesions of PDAC: mucinous cystic neoplasms (MCNs) and intraductal papillary mucinous neoplasms (IPMNs). Endoscopic ultrasound-guided fine needle biopsies are becoming an increasingly valuable tool in the diagnosis of pancreatic lesions with paraffin-embedded material facilitating ancillary tests. Pathological examination of tissue samples from the pancreas allows typing and grading of neoplasms, and in resections will also provide information on stage, resection margin status and response to any neoadjuvant treatment given. It plays a vital role in the multidisciplinary care of patients with pancreatic diseases and, in the future, is very likely to form the basis for assessment of biomarkers in tissue sections for tumour genotype-specific treatment stratification. This review summarizes types of tissue samples, followed by descriptions of the most important non-neoplastic and neoplastic solid and cystic lesions including recent developments.