Choroid plexus carcinoma.

The authors report a case of carcinoma of the choroid plexus and review the 22 cases reported since 1844 that adhere to the criteria for primary choroid plexus carcinoma. Two-thirds of the tumors are found in children and all of these are located in the lateral ventricles. In adults most of the tumors are present in the fourth ventricle. Differentiation of this neoplasm from papillary ependymomas, choroid plexus papillomas, secondary carcinomas, and "collision tumors" is discussed.