Pseudoviral hollow-cored vesicles in multiple sclerosis brain

Summary Novel, superficially virus-like hollow-cored particles 50–60 nm in diameter were found in the perivascular extracellular space of the brain from a patient who died with acute multiple sclerosis (MS). It is concluded that they are not virions but are derived from myelin undergoing vesicular demyelination. This case demonstrates the need for caution in the interpretation of unusual electron microscopic appearances.