Primary solid pancreatic tumors: recent imaging findings updates with pathology correlation.

The imaging findings of primary solid pancreatic tumors have long been studied and are generally well-established. However, interestingly enough, a wealth of new information has recently appeared in the literature, including the imaging findings of novel or previously seldom-addressed pathological entities as well as atypical imaging findings of common tumors, both of which are well-correlated with the pathology findings. 5 %-14 % of pancreatic ductal adenocarcinomas have been reported on dynamic contrast-enhanced computed tomography to be isoattenuating, and thus making the imaging diagnosis challenging. The imaging-pathology correlation in such isoattenuating tumors is presented along with a discussion regarding the early imaging detection of pancreatic cancers. Colloid (or mucinous non-cystic) pancreatic cancer may resemble a less harmful cystic lesion due to its abundant extracellular mucin, and thus requiring caution in the image interpretation. Serotonin-producing neuroendocrine tumors have recently been recognized as a separate entity from usual neuroendocrine tumors. Exuberant fibrosis caused by serotonin metabolites and scarce tumor cells creates a unique pattern of pancreatic ductal obstruction seen on imaging. Small solid pseudopapillary tumors appear as unencapsulated, completely solid lesions with gradually increasing enhancement after contrast administration, unlike typical solid pseudopapillary neoplasms that present as a large mixed solid and degenerated cystic or hemorrhagic mass encapsulated by a thick capsule and which, therefore, tend to be misdiagnosed on imaging. Solid serous adenoma is a rare, solid variant of serous cystadenoma and appears on imaging as a hypervascular, solid nodule due to its genuinely microscopic cystic, alveolar, and ectatic tubular tumor architecture.