Intraductal papillary mucinous tumors of the pancreas.

Intraductal papillary mucinous tumors (IPMTs) are benign and malignant lesions that arise from the epithelial lining of main pancreatic duct and/or branch pancreatic ducts, with excessive mucin production (especially hyperplastic/adenomatous variety). Based on the degree of cytoarchitectural atypia on microscopic examination, IPMTs are classified as benign, borderline, carcinoma in situ and invasive tumors. Imaging examinations are very important to establish the diagnosis. Two or more tests are usually required. Transabdominal ultrasound, endoscopic ultrasound, computed tomography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangio-pancreatography have been used for the diagnosis of IPMTs. The correct diagnosis, achieved until recently only with endoscopic retrograde cholangiopancreatography, can be currently obtained with non-invasive imaging modalities, particularly computed tomography and magnetic resonance imaging. Confirmation of the diagnosis requires, however, endoscopic-ultrasound fine-needle aspiration biopsy, followed by cytological or microhistological exams. The natural evolution of IPMTs is still not clear and the management is consequently still evolving.