Disseminated choroid plexus papilloma. An ultrastructural study.

Choroid plexus papilloma is a rare intracerebral neoplasm that occasionally disseminates along the neuraxis. The fine structure of such a metastatic papilloma appears to correspond very closely to that of normal choroid plexus. Lack of capillary endothelial pores is the only meaningful difference. There does not appear to be an ultrastructural feature that is unique to disseminating choroid plexus papilloma.