Brain stem lesions

A-Same lesions as that occur in the brain and cerebellum.

B-It could be 

1-Hemorrhage.                         HIT CC

2-Infarction.

Could be unilateral or bilateral.

Due to basilar artery occlusion.

3-Tumors.

-Brain stem glioma causes compression of the fourth ventricle posteriorly.

-Normally the fourth ventricle has a convex upper border, in case of brain stem space occupying lesion, it becomes concave upper border with compression of the ventricle itself.

-This tumor can extends in the peduncle causing compression of the ventricle from the right or left.

How to differentiate between tumor and infarction of the brain stem

-By clinical where the patient with the latter is complaining from multiple cranial nerve palsies especially 6 nerve.

-By degree of expansion of the brain stem where in the latter does not expand to much as the former (the brain stem is still taking its normal configuration).

-By the age of the patient where in the latter it occurs in old age while in the former is specific to pediatric group.

-Brain stem glioma in children usually doe not take contrast (in 50% of cases).

-So any mass in the brain stem if it does not take contrast, it will be a brain stem glioma.

-If it take contrast, it will be glioblastoma multiform. 

-Non enhanced gliomas are

Diffuse glioma.

infiltrating glioma

Brain stem glioma.

-It can make exophytic extension in the prepontine cistern surrounding basilar artery.

4-Calcification.

5-Cysts.