The posterior fossa is a small space located at the back of the skull, near the brainstem and cerebellum. The posterior fossa has limited space. If a tumor grows in this area, it can block the flow of spinal fluid and cause increased pressure on the spinal cord and brain.
Most tumors of the posterior fossa are removed with surgery, even if they are not cancerous. Depending on the type and size of the tumor, radiation treatment may also be used after surgery.