MR findings on primitive neuroectodermal tumors.

Primitive neuroectodermal tumors (PNETs) are highly cellular primitive CNS neoplasms that resemble microscopically the undifferentiated cells of the germinal matrix of the primitive neural tube. These tumors exhibit a highly malignant behavior with a tendency to disseminate along the CSF pathways. Previous descriptions of the neuroradiological findings in patients with PNET were published prior to the clinical application of magnetic resonance (MR) imaging. We describe our experience with the MR evaluation of four patients with pathologically proven PNET.