Melanosis of the choroid plexus, ependyma, subependymal neuroglia, and dentate and trigeminal motor nuclei: observations on the choroidal and ependymal cilia.

Melanosis of the choroid plexus, ependyma, subependymal neuroglia of the fourth ventricle, and dentate and trigeminal motor nuclei was found in a 50-year-old man who died with cor pulmonale, hypertensive cardiovascular disease, and intracerebral hemorrhage. This case is the first known example of melanosis not associated with neurocutaneous melanosis to involve multiple structures of the brain. Nonenzymatic conversion of lipofuscin into melanin is suggested as the mechanism of the melanosis. Cilia of the choroidal epithelium and ependyma were identified in this case, despite a long delay in postmortem examination. These observations on choroidal epithelium confirm previous reports that the choroid plexus of man is ciliated, as in other mammals and lower vertebrates.