Rapid regrowth of an atypical choroid plexus papilloma located in the cerebellopontine angle.

Choroid plexus papilloma usually occurs in the lateral or the fourth ventricle. Primary choroid plexus papilloma of the cerebellopontine angle, as described here, is an uncommon lesion. A 42-year-old man presented with a 1-month history of dysphagia and gait unsteadiness. CT scans and MRI showed a large extra-axial tumor in the right cerebellopontine angle. Pathological study revealed that the lesion was choroid plexus papilloma. Repeat imaging conducted 1 year after the operation showed that the tumor had recurred with distinct cystic features. Pathological examination again revealed increased mitotic activity and supported a diagnosis of atypical choroid plexus papilloma.