Primary carcinoma of the choroid plexus in the lateral ventricle.

Primary carcinomas of the choroid plexus are rare and occur more frequently in children than in adults. They have been posing a problem in their differential diagnosis from benign papilloma of the choroid plexus, ependymoma, and metastatic tumors of extracranial origin. A case of a 31-year-old woman with primary carcinoma of the choroid plexus in the trigone is reported. Electron microscopic and immunohistochemical studies are helpful, but not decisive yet, to reach the diagnosis. The literature is reviewed.