Solitary Enhancing Intradural, Extramedullary Lesions

Case A: An intradural, extramedullary, avidly enhancing, T2 hypointense, posterior dural-based mass with dural enhancement centered at the level of the cervicothoracic junction. The mass fills the central canal and markedly compresses the cord. Important clues to the diagnosis of meningioma are central calcification, which is evident as hypointensity on T2-weighted imaging along with the dural enhancement associated with the lesion.

Case B: An intradural, extramedullary, peripherally enhancing, T2 hyperintense mass at the level of T12. Mass effect on the adjacent cord is noted. The prominent T2 hyperintensity of the lesion and the rim enhancement are important clues to the diagnosis of nerve sheath tumor (schwannoma).

Case C: An intradural, extramedullary, heterogenous, avidly enhancing mass demonstrating heterogenous T2 hyperintensity is centered below the conus medullaris. Although lesions of the cauda equina or filum terminale are nearly impossible to distinguish from each other on imaging, pathology findings proved that this lesion was a schwannoma.

Case D: An intradural, extramedullary, T2 mildly hyperintense, avidly enhancing, smoothly marginated mass that is displacing cauda equina nerve roots and filling the thecal sac at the level of L1/L2. The conus terminates above the level of this lesion. Although lesions of the cauda equina or filum terminale are nearly impossible to distinguish from each other on imaging, pathology findings proved that this lesion was a myxopapillary ependymoma of the filum terminale.