Neuropathologic Studies of Acute Multiple Sclerosis Mimicking Acute Encephalitis
Neuropathologic findings of acute multiple sclerosis mimicking acute encephalitis were described. The patient was a 42-year-old man with acute febrile encephalitic symptoms and signs such as high fever, unconsciousness and convulsive seizures, and a monophasic course of 18 days duration. Pathologically, numerous inflammatory demyelinating lesions were scattered mainly in the cerebral and cerebellar white matter, the internal capsules, the putamen, the brainstem and the optic nerves. In particular, the demyelinating lesions of the brainstem were extensive and confluent, whereas those in the right occipital lobe were small and perivenous, reminiscent of acute disseminated encephalomyelitis. Axons in these demyelinating lesions were well preserved, with a considerable number of macrophages and partial proliferation of protoplasmic astrocytes. There were no demyelinating lesions of concentric sclerosis type, which may occur in cases with acute multiple sclerosis. Pathological features in this case were typical of acute multiple sclerosis despite the symptoms and signs mimicking acute encephalitis and a clinical course of only 18 days duration.