Dural invasion by craniofacial and calvarial neoplasms: MR imaging and histopathologic evaluation.

The authors prospectively correlated results of magnetic resonance (MR) imaging and histologic examination of the dura in 17 patients with craniofacial and calvarial neoplasms and possible intracranial extension. Contrast material-enhanced MR imaging revealed dural enhancement in 14 patients and no enhancement in three. In four cases, the dura deep to the tumor appeared as a continuous band of enhancement and there was a thin unbroken hypointense zone between the dura and the tumor. Histologic examination in these four patients revealed only dural inflammation without neoplastic spread. In 10 patients, there was a break in the continuity of the enhancement of the underlying dura or a portion of the dura and overlying enhancing tumor could not be separated on MR images. The hypointense zone was focally absent in nine of these cases, and in all 10 there was invasion of the dura by adjacent tumor. Among the other three patients, in whom dural enhancement was not discernible, one had dural invasion by tumor while the other two did not.