ABSTRACT
Objective To investigate the routes and MR imaging manifestations of meningeal involvement by nasopharyngeal carcinoma (NPC) with pathological correlation. Methods Twenty five NPC patients with involvement of meninges were included into the study. All patients underwent both unenhanced and Gd DTPA enhanced MR imaging examinations. Surgical and pathological findings were correlated with MR imaging manifestations in 9 patients. Positive cytology was found in only 1 of the 25 patients. Results There were three main routes for meningeal involvement in NPC patients: (1).through the natural bony channels (foramens) of the skull base; (2).through direct bony erosion of the skull base; and (3).Through hematogenous spread. Dura mater was very frequently involved, being seen in 24 patients; pia mater was involved in only one patient. Irregular, patchy thickening in the form of “necklace”, nodules, or mass with obvious enhancement was the major MR feature of meningeal involvement by NPC. In one patient with choroid plexus involvement, dilatation of the lateral ventricles, subependymal nodules with patchy thickening were observed. Conclusion MR imaging with Gd DTPA enhancement was very useful to demonstrate the presence, location and extent of meningeal involvement in NPC patients.