Posterior fossa tumor

Alternative Names

Infratentorial brain tumors; Brainstem glioma

Definition of Posterior fossa tumor

Posterior fossa tumor is a type of brain tumor located in or near the bottom of the skull.

Causes, incidence, and risk factors

The posterior fossa is a small space in the skull, found near the brain stem and cerebellum. The cerebellum is the part of the brain responsible for movement, balance, and coordination.


Symptoms occur very early with posterior fossa tumors and may include:

Signs and tests

Diagnosis is based on thorough history and physical examination, followed by imaging tests. The best way to look at the posterior fossa is with an scan. CT scans are usually not helpful.


Most tumors of the posterior fossa are surgically removed, even if they are noncancerous. There is limited space in the brain area, and the tumor can press on delicate structures if it grows.

Expectations (prognosis)

Prognosis depends on early detection. Complete obstruction to the flow of spinal fluid causes herniation and death. If tumors are recognized before this point, surgery is associated with good, long-term survival.


David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. – 3/2/2010

ADAM Medical Encyclopedia

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