Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas.

Solid lesions of the pancreas represent a heterogeneous group of entities that can be broadly classified as either neoplastic or nonneoplastic. Neoplastic lesions include pancreatic adenocarcinoma, pancreatic neuroendocrine tumor, solid pseudopapillary tumor, pancreatoblastoma, pancreatic lymphoma, metastases to the pancreas, and rare miscellaneous neoplasms. Nonneoplastic lesions include focal pancreatitis, fatty infiltration-replacement, intrapancreatic accessory spleen, congenital anomalies such as prominent pancreatic lobulation and bifid pancreatic tail (pancreatic bifidum), and rare miscellaneous lesions (eg, pancreatic sarcoidosis, Castleman disease of the pancreas). A variety of imaging modalities are available for assessing these solid lesions, including ultrasonography (US), computed tomography (CT), magnetic resonance imaging, endoscopic US, and hybrid nuclear imaging techniques such as single photon emission computed tomography-CT and positron emission tomography-CT, each of which has its own strengths and limitations. Accurate diagnosis can be challenging, and use of a multimodality imaging approach is often helpful in equivocal or complex cases. Knowledge of relevant clinical information and key radiologic features is essential for confident lesion characterization and differentiation.