Solitary asymptomatic plaque of demyelination in the medulla oblongata.

Clinically benign and clinically silent multiple sclerosis is now recognized. The corresponding plaques of demyelination in such cases are usually located in silent areas of the brain. We report a case where a solitary 3 x 3 mm plaque of demyelination was incidentally found in the medulla oblongata at autopsy. Although the plaque should have produced sensory symptoms by virtue of its location, no such history was obtainable even after direct questioning of the spouse of the deceased. The case illustrates that a single episode of demyelination may take place within the CNS without recurrence, and that a demyelinating plaque may be asymptomatic due to a functionally benign local effect, and not only by location in a silent area of the brain.