Patient History
Clinical findings suggesting of left trigeminal schwannoma with brainstem compression.
Findings
Pre- and postcontrast MR was performed of the brain and skull base.
Brain: Sagittal images show the corpus callosum to be intact. No abnormal pineal region masses are seen. The pituitary gland is not enlarged. There is no evidence of Chiari malformation. Diffusion imaging shows no evidence of recent infarct. Susceptibility weighted imaging shows no evidence of hemosiderin staining. The axial FLAIR and T2 weighted images show some prominence of the sulci and ventricles. There is no evidence of obstructive hydrocephalus.
Skull base: The study demonstrates an approximately 3.3cm x 2.5cm homogeneously enhancing extra-axial mass located in the left cerebellopontine angle region. The posterior aspect of this mass extends to the porus acusticus with a very small component extending into the medial aspect of the internal auditory canal. The anterior aspect of this mass extends into the lateral aspect of the left prepontine cistern and continues anteriorly through Meckel's cave with complete involvement of Meckel's cave. There is no direct extension into the cavernous sinus, however, there is some mild effacement of the lateral wall of the left cavernous sinus. Left cranial nerves 3 and 6 are visualized in the left cavernous sinus. The superior aspect of the mass extends into the left perimesencephalic cistern. The inferior aspect of the mass extends along the dorsal aspect of the clivus to the level of the transverse segments of the petrous portion of the carotid arteries. The mass medially displaces the left middle cerebellar peduncle. There is partial effacement of the left 4th ventricle. However, there is no evidence of ventriculomegaly of the lateral or 3rd ventricle. The mass involves the expected location of the cisternal portions of left cranial nerves 5, 6, 7 and 8.
Conclusions
1. A 3.3 x 2.5cm homogeneously enhancing extra-axial mass located in the left cerebellopontine angle region and extends anteriorly into left Meckel's cave. The findings are most consistent with a meningioma.
2. Mass effect on the left middle cerebellar peduncle with mild partial effacement of the 4th ventricle. No evidence of obstructive hydrocephalus of the lateral ventricles.
3. No evidence of recent infarct.
