Paragangliomas of the temporal bone: high-resolution CT studies

Seventeen patients with 15 surgically proved paragangliomas involving the temporal bone and parapharyngeal spaces were examined with high-resolution computed tomography (CT). Scans were obtained in multiple axial (0 degree, 30 degrees) and coronal (70 degrees, 105 degrees) section planes using 1.5-mm collimation and table incrementation. The purpose of this study was to demonstrate the utility of HRCT in assessing tumor extent and size, with particular emphasis on intrinsic temporal bone invasion. The most characteristic HRCT signs of paraganglioma include: jugular fossa expansion, soft-tissue mass in the hypotympanum and sinus tympani, permeation of the infracochlear surface, dural ballooning adjacent to the jugular fossa (indicative of epidural tumor), anterior displacement of parapharyngeal fat planes, and extension into the proximal aspect of the eustachian canal. It is concluded that HRCT is the single most efficacious examination to determine tumor extent, especially when intratemporal invasion has occurred, and to define other additional clinically unsuspected lesions.