MR demonstration of ectopic fourth ventricular choroid plexus in Chiari II malformation.

Abstract

An enhancing nodule was seen on T1-weighted enhanced scans at the tip of the caudally displaced cerebellar vermis in three patients with Chiari II malformation. The enhancing fibrovascular nodule found at the base of the cerebellum in patients with Chiari II malformation represents ectopic choroid plexus and should not be confused with a pathologic mass.