Cystic tumors of the pancreas

Physicians are increasingly being confronted with the diagnosis, differential diagnosis, and management of cystic lesions of the pancreas. Owing to recent refinements in cross sectional imaging, an increasing number of cystic lesions have been identified in asymptomatic patients as well as in patients presenting with abdominal pain, pancreatitis, or jaundice. Therefore, there has been a significant increase in awareness of cystic lesions of the pancreas. In the clinical setting, it is crucial to differentiate between benign and malignant lesions as the management of these conditions is entirely different. Recently, increasing experience with these lesions has come to a refinement of the pathological classification of cystic neoplasms and of their natural history. These tumors encompass a spectrum of benign, malignant, and borderline neoplasms that either are primarily cystic or result from the cystic degeneration of solid tumors. Among these neoplasms, serous cystadenomas, intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms, and solid pseudopapillary neoplasms represent the majority of the cases encountered in practice. Serous cystadenoma, also referred to as microcystic cystadenoma, is typically found in women over the age of 60 years with unspecific complaints of abdominal pain. Typical serous cystadenomas are composed of honey-comb like microcysts varying in size from 0,2 to 2,0cm. Oligocystic variants have also been reported. The presence of a central scar is a highly diagnostic feature that is found in about 20% of these tumors. Lobulated contours have been demonstrated to be a specific finding in comparison with pseudocysts. IPMNs typically occur in elderly patients and are more common in men. IPMN is characterized by cystic dilatation of a main or a side branch duct that contains thick mucoid material. These tumors are classified into the main duct type, branch duct type, and combined type. The demonstration of a communication with the pancreatic ductal system is a key feature of IPMN. The presence of mural nodes and a segmental or diffuse dilatation of the main pancreatic duct greater than 15mm in diameter has been reported as indicative of the development of malignant disease. Mucinous cystic neoplasms, also known as macrocystic adenomas/cystadenocarcinomas occur most frequently in women in their sixth decade. Mucinous cystic neoplasms are typically large lesions at the time of diagnosis, are usually multilocular with well-defined borders and have thick fibrous walls. Characteristically, they lack a communication with the pancreatic ductal system. Solid pseudopapillary neoplasms are found most commonly in young females. The tumor tends to be a large, well-circumscribed, and slowly growing mass with a variety of internal appearances, from purely cystic to completely solid. The appearance of the tumor typically depends on the degree of internal hemorrhage or necrosis. Imaging is indispensable in the evaluation of patients with cystic pancreatic lesions. Multidetector row CT has become the preferred method for both initial detection and characterization of cystic lesion of the pancreas. Magnetic resonance imaging including MRCP accurately depicts the morphologic features of the cysts and has the advantage of demonstrating the relationship of the cystic lesion to the pancreatic duct. Based on morphologic features, pancreatic cystic lesions can be classified into four subtypes: unilocular cysts, microcystic lesions, macrocystic lesions, and lesions with a solid component. Lernziele: Familiarity with the range of imaging features is important for accurate diagnosis and management of cystic pancreatic lesions. Korrespondierender Autor: Brambs HJ Universitatsklinikum Ulm, Klinik fur diagnostische und interventionelle Radiologie, Steinhovelstrase 9, 89075 Ulm E-Mail: hans-juergen.brambs@medizin.uni-ulm.de