Cystic lesions of the pancreas

Abstract

Although cystic tumors of the pancreas are relatively rare, they constitute an increasingly important category. Advances in imaging and interventional techniques and the sharp drop in the mortality rate of pancreatic surgery have rendered pancreatic biopsies and resections commonplace specimens. Consequently, in the past two decades, the nature of many cystic tumors in this organ has been better characterized. The names of some existing entities were revised; for example, what was known as papillary-cystic tumor is now regarded as solidpseudopapillary tumor. New entities, in particular, intraductal papillary mucinous neoplasm and its variants, such as oncocytic and intestinal subtypes were recognized. The importance of clinical and pathologic correlation in the evaluation of these lesions was appreciated, in particular, with regards to the multifocality of these lesions, their association with invasive carcinomas, and thus their 'preinvasive' nature. Consensus criteria for the distinction of these from the ordinary precursors of adenocarcinoma, the pancreatic intraepithelial neoplasia, were established. The definition of mucinous cystic neoplasms was refined; ovarian-like stroma has now become almost a requirement for the diagnosis of mucinous cystic neoplasia, and defined as such, the propensity of these tumors to occur in perimenopausal women became even more striking. The validity and clinical value of classifying the pancreatic cysts of mucinous type as adenoma, borderline, CIS and invasive have been established. Related to this, the importance of thorough sampling in accurate classification of these mucinous lesions was recognized. Greater accessibility of the pancreas afforded by improved invasive as well as noninvasive modalities has also increased the detection of otherwise clinically silent cystic tumors, which has led to the recognition of more innocuous entities such as acinar cell cystadenoma and squamoid cyst of pancreatic ducts. As the significance of the cystic lesions emerged, cystic forms of otherwise typically solid tumors were also better characterized. Thus, significant developments have taken place in the classification and our understanding of pancreatic cystic tumors in the past few years, and experience with these lesions is likely to grow exponentially in the coming years. Modern Pathology (2007) 20, S71-S93.

Pancreatic cysts: etiology, diagnosis and management

“…Post-inflammatory pancreatitis-related pseudocysts are most common but some other infrequent pancreatic pseudocysts have been described in the literature: paraduodenal wall cysts (cystic dystrophy) and infection-related pseudocysts (parasitic and tuberculous cysts) [1].…”

“…There are different classifications of pancreatic cystic lesions in the literature. According to epithelial lining of the pancreatic cysts, they are divided into true cysts (lined with the epithelium) and pseudocysts (without the epithelium) [1]. According to development type and etiology, they are divided into primary and secondary cysts [2,3].…”

“…Secondary lesions are a result of the transformation of solid pancreatic tumors (adenocarcinomas and neuroendocrine tumors) in the cystic forms [2,3]. Pseudocysts due to acute and chronic pancreatitis are most common pancreatic cysts (70%) [1][2][3][4][5][6]. Pancreatic cystic neoplasms constitute less than 1% of all pancreatic tumors [1].…”

“…Pseudocysts due to acute and chronic pancreatitis are most common pancreatic cysts (70%) [1][2][3][4][5][6]. Pancreatic cystic neoplasms constitute less than 1% of all pancreatic tumors [1]. Proper differential diagnosis of the pancreatic cysts is very important for decision regarding management.…”

“…Therefore, descriptive "pancreatic cystic lesions" is used to define all pancreatic cysts [1,2]. There are different classifications of pancreatic cystic lesions in the literature.…”