 Introduction/Background Incidental pancreatic cysts are now increasingly detected on imaging studies performed for unrelated indications. [1-3]. Both increased imaging utilization and improved cross-sectional technique are responsible for the more frequent detection of progressively smaller cysts [4-6]. The most commonly encountered pancreatic cysts include intraductal papillary mucinous neoplasms (IPMNs), serous cystadenoma, mucinous cystic neoplasm (MCN), and pseudocysts [6,7]. There is a very small risk that an incidental pancreatic cyst may be malignant [8]. For instance, an incidental pancreatic cyst on MRI has a 10 in 100,000 chance of being a mucinous invasive malignancy and a 17 in 100,000 chance of being a ductal carcinoma [8]. The risk of malignant transformation in pancreatic cysts is estimated to be 0.24% per year [9], varying according to histologic subtype [7,10]. Yet there is considerable overlap in the imaging appearance of histologically distinct pancreatic cysts, particularly those <3 cm in size, with over 60% of cysts lacking a specific radiologic appearance on CT or MRI [6]. Another important feature in the natural history of pancreatic cysts is the small risk of pancreatic adenocarcinoma developing at a separate site within the pancreas [4,7,11-13]. Although the risk of cyst-related or concomitant pancreatic malignancy is small, there is a need to characterize incidental pancreatic cysts effectively at initial imaging in order to guide management. Appropriate imaging evaluation of incidental pancreatic cysts is critical because morphology determines management. As an example, surveillance is generally recommended for cysts <3 cm in size without worrisome features or high-risk stigmata [7,13]. Cysts with worrisome features undergo sampling with endoscopic ultrasound fine-needle aspiration (EUS-FNA) [8-10] and those with high-risk stigmata are typically resected [8-10].
Pancreatic Cyst.  Introduction/Background Incidental pancreatic cysts are now increasingly detected on imaging studies performed for unrelated indications. [1-3]. Both increased imaging utilization and improved cross-sectional technique are responsible for the more frequent detection of progressively smaller cysts [4-6]. The most commonly encountered pancreatic cysts include intraductal papillary mucinous neoplasms (IPMNs), serous cystadenoma, mucinous cystic neoplasm (MCN), and pseudocysts [6,7]. There is a very small risk that an incidental pancreatic cyst may be malignant [8]. For instance, an incidental pancreatic cyst on MRI has a 10 in 100,000 chance of being a mucinous invasive malignancy and a 17 in 100,000 chance of being a ductal carcinoma [8]. The risk of malignant transformation in pancreatic cysts is estimated to be 0.24% per year [9], varying according to histologic subtype [7,10]. Yet there is considerable overlap in the imaging appearance of histologically distinct pancreatic cysts, particularly those <3 cm in size, with over 60% of cysts lacking a specific radiologic appearance on CT or MRI [6]. Another important feature in the natural history of pancreatic cysts is the small risk of pancreatic adenocarcinoma developing at a separate site within the pancreas [4,7,11-13]. Although the risk of cyst-related or concomitant pancreatic malignancy is small, there is a need to characterize incidental pancreatic cysts effectively at initial imaging in order to guide management. Appropriate imaging evaluation of incidental pancreatic cysts is critical because morphology determines management. As an example, surveillance is generally recommended for cysts <3 cm in size without worrisome features or high-risk stigmata [7,13]. Cysts with worrisome features undergo sampling with endoscopic ultrasound fine-needle aspiration (EUS-FNA) [8-10] and those with high-risk stigmata are typically resected [8-10].