Not all pancreatic cystic lesions are the same: lesson from a case with three different coexisting neoplasms.

An asymptomatic 79-year old woman presented with a 40 mm pancreatic cystic lesion, located in the pancreatic body-tail and consistent with branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) without "high risk stigmata". During a 4-year follow-up period, imaging showed no mural nodules or main pancreatic duct dilation, and serum CEA and CA19.9 were within normal range. Later, computed tomography showed a rapid increase in cyst size up to 59 mm, which led to a clinical suspicion of malignant transformation. The patient underwent distal pancreatectomy, and final histology revealed the presence of three distinct pancreatic neoplasms: serous cystadenoma (SCA), BD-IPMN, and well-differentiated G1 neuroendocrine tumour (PanNET-G1). The co-occurrence of pancreatic neuroendocrine and exocrine tumours is exceedingly rare. To the best of our knowledge, this is the first reported case of the concomitant presence of three different pancreatic tumors in the same pancreatic specimen arose adjacent one to each other within the same macroscopic lesion.