A new variant of progressive encephalomyelitis with rigidity associated with cerebellar ataxia and dementia: correlation of MRI and histopathological changes. A case report.

A 27 year-old patient developed a progressive neurological multisystem disorder. Initial signs were cerebellar ataxia and dementia, followed by rigidity and oculomotor dysfunction. Myoclonus was not present. MRI showed a marked atrophy of the spinal cord, the cerebellum, and mild (sub)cortical atrophy. CSF contained oligoclonal bands, but no anti-glutamic acid dehydrogenase antibodies. He died 33 months after onset of symptoms. Autopsy revealed widespread neuropathological alterations including perivascular lymphocytic cutting, neuronal cell loss, and micro/astrogliosis the distribution of which corresponded to the changes seen in MRI. The diagnosis of progressive encephalomyelitis with rigidity was pathohistologically confirmed. Brain samples were negative for neurotrophic viruses tested by polymerase chain reaction. A new variant of this rare disorder is described initially presenting with ataxia and dementia, but without myoclonus.