Choroid plexus papillomas of the foramen of Luschka: MR appearance.

Choroid plexus papillomas are rare intracranial neoplasms that are most commonly found in the trigone of the lateral ventricles or in the fourth ventricle. Rare cases of extraventricular choroid plexus papillomas have been reported within the cerebellopontine (CP) angle cistern [1-6]. Such cases have been described as either extending from the fourth ventricle via the foramen of Luschka or arising directly from the CP angle cistern. We report MR findings in two unusual cases of choroid plexus papillomas that appeared to arise from within the foramen of Luschka without an associated intraventricular component. In the first case, the tumor presented as an expansile mass of the foramen of Luschka, whereas in the second case the tumor arose from the foramen of Luschka and extended to the CP angle cistern.