The Common Vein Copyright 2010
Definition
A brainstem glioma is a tumor generally seen in children constituting up to 20% of CNS neoplasms seen in children. While a majority of them arise from within the pons where they tend to be high grade and diffusely infiltrative, there are several different subtypes which are less aggressive. This tumor is of unknown etiology however there is an association with brainstem gliomas and neurofibromatosis type 1.
Pathologically these tumors may be low grade or high grades astrocytomas with the same features as astrocytomas found elsewhere. Features more suggestive of a higher grade include nuclear atypia, high cellularity, mitotic figures and necrosis.
Although most lesions are infiltrative tumors that arise from within the pons, they may occur elsewhere and be relatively well circumscribed, noninfiltrative or even exophytic masses. As with other tumors, presenting symptoms are based on lesion location. There is a wide range of symptoms including cranial nerve defects, symptoms of increased intracranial pressure from hydrocephalus, and personality changes.
MRI is the imaging exam of choice for brainstem gliomas. Infiltrating gliomas may have the appearance of an expanded T1 hypointense T2 hyperintense pons. When located within the tectum, there may be T1 and T2 hyperintensity with higher density seen on CT due to calcification. Other brainstem gliomas may have a cyst with enhancing mural nodule appearance.
Treatment for brainstem gliomas is variable based on location and type. Diffuse pontine gliomas are generally treated with radiation. Tectal gliomas can be treated with shunting of the hydrocephalus. Depending on location, focal brainstem gliomas may be surgically removed. Other options include chemotherapy and radiation.
References
Kieran, MN and Marcus KJ, Focal brainstem glioma, UpToDate Updated August 2009.