Meningiomas are slow-growing tumors of cells of the chorionic villi. These tumors are usually located adjacent to the dura mater.

This tumor may increase the intracranial pressure.

Meningitis is an inflammation of the meninges.

This condition arises from an infestation of bacteria or viruses.

Viral meningitis is cuased by mumps virus and coxsackievirus, whereas bacterial meningitis is cuased by the influenza and pneumococcal bacteria.

The choroid plexus ultimately becomes congested with white blood cels, and endothelial cells swell, which restricts CSF flow.