**3. Diagnostic perspectives and management options**

The current use of imaging modalities has allowed some important results in the nosographic study: certain distinction between postnecrotic acute or chronic pseudocysts and cystic tumors; among the cystic neoplasms, the identification of clinical pathological features that allow recognizing some kinds of cystic tumors with several perspective of neoplastic evolution.

Cystic and intraductal mucinous neoplasms are pancreatic tumors of ductal origin and are characterized by cysts lined by mucinous epithelium.

Cystic tumors of the pancreas have the characteristic of precursor: they may be associated with or progress to invasive carcinoma. They are the preinvasive neoplasms, as the pancreatic intraepithelial neoplasms, but these tumors form clinically detectable masses, usually before that they become invasive, as the gastrointestinal adenoma. From these data, we take the therapeutic decision. A rough and summary monitoring of this setting clearly shows that cystic lesions are becoming increasingly more common, particularly among resection specimens. The reasons for this increase in frequency are various: important improvement in imaging techniques allows increased detention of clinically silent neoplasms; the majority of the cystic tumors are surgically removable because they are non‐infiltrative in their evolution, and finally great decrease in postoperative complications and mortality rate of pancreatic surgery. The increased imaging and pathological studies and confirmation of all pancreatic cystic lesions result in better knowledge of these lesions.

A rough estimate of relative frequency of the pancreatic cystic lesions from the published data in the literature has been reported [5, 9]: pseudocysts (pancreatitis associated), 30%; IPMNs, 20%; MCNs, 10%; SCNs, 20%; acinar cell cystadenocarcinomas, lymphoepithelial cysts and lymphangiomas, <5%; SPPNs, <5%; cystic ductal adenomas, <5%; CPENs and metastasis, <5%.

The more simple classification of pancreatic cystic lesions subdivides two main classes: non‐ neoplastic cysts with pseudocysts non‐lining and simple or congenital cysts, retention cysts that reach 80% of cases; neoplastic cysts or lining lesions that set up 20% of cases and can be defined pancreatic cystic neoplasms (PCNs) [7]. The main problem in the management of these lesions is the sure distinction between non‐neoplastic cysts (pseudocysts, retention, and simple cysts) and pancreatic cystic neoplasms. Moreover, in the latter group, we need to distinguish non‐mucinous from mucinous cysts that are considered being premalignant lesions. The therapeutic choices can be very different from simple follow‐up to surgical resection. The WHO [1, 10] histological classification of tumors of exocrine pancreas and classification of pancreatic cystic lesions, integrated and updated by Kosmahl et al. [3] should be valuable references in the development of this subject. The specific epidemiology, histological features, imaging characteristics, clinical evolution, and therapeutic choices of the most frequent lesions as well as rare forms are described in each specific section.
