[A unilateral large demyelinating lesion in the cerebral white matter with slowly progressive hemiplegia and intrathecal JC virus antibody production].
A 59-year-old male patient presented in 1991 with left-sided hemiplegia and hemihypesthesia and left homonymous hemianopsia, which had developed for the preceding 12 months. The cerebrospinal fluid (CSF) level of protein was mildly elevated, oligoclonal IgG band was initially negative, but finally positive and myelin basic protein was absent. Magnetic resonance imaging and X-ray computed tomography (CT) of the brain revealed a unilateral demarcated lesion extending around the posterior horn and triagular part of the right lateral ventricle, apparently capped by remarkably gadolinium enhancement at its front, which had no mass effect, and several small isolated plaques were also observed in other areas of the brain. All lesions appeared as high intensity areas on T2 weighted images and hypodense areas on CT. The JC virus hemagglutination-inhibition antibody titers were 1:32 in serum and 1:8 in CSF; the antibody titer ratio and index both suggested an intrathecal antibody production. Pathological examination of brain biopsy specimen taken from the large lesion demonstrated profound demyelination with preservation of axons, a large number of macrophages and spotted perivascular lymphocyte cuffings. Based on this experience, we discussed the features in this case which differentiated it from multiple sclerosis, leukodystrophy and typical progressive multifocal leukoencephalopathy (PML). Diffuse-disseminated sclerosis or transitional sclerosis was most likely so far as the clinical picture, imaging and histology were concerned. However, we implicated the possible involvement of JC virus infection to the etio-pathogenesis of the demyelinating lesions in view of the intrathecal JC virus antibody production in CSF observed in this case.(ABSTRACT TRUNCATED AT 250 WORDS)