Brain Stem Glioma

            Most brain stem gliomas are relatively benign initially but frequently evolve to a higher grade. They usually present with a cranial nerve palsy, most often involving the 6th or 7th nerves. The pons is the common location, but they also occur in the medulla and midbrain. These tumors infiltrate the brain stem and induce surrounding vasogenic edema in the brain parenchyma. Since both the tumor and edema are hyperintense on T2-weighted images, tumor margins tend to be indistinct and poorly defined.

            Brain stem gliomas are relatively homogeneous masses without much cystic change, necrosis, vascularity or calcification. About 50% of cases will show mild enhancement. As the gliomas grow, they enlarge the brain stem, producing effacement of the basal cisterns, anterior displacement of the basilar artery against the clivus, and compression and posterior bowing of the fourth ventricle. Hydrocephalus is often present. Exophytic growth is a well-known feature of these tumors.  

{To return to cases, use the "Back " button on the Toolbar}