[Frequency of metastases of extracranial tumours in the choroid plexus (author's transl)].

5% of malignant extracranial tumours metastasize into the choroid plexus, especially tumours with a higher grade of malignancy. Metastases in the choroid plexus are more frequent than mestastases in the brain corresponding to the relation of weight of choroid plexus and brain. This fact can be explained with the vascularisation by capillaries containing endothelial pores. It remains obscure whether there are other special biochemical or immunological mechanisms too, causing the frequency of metastases in the choroid plexus.