Autopsy case of the cerebellar form of progressive multifocal leukoencephalopathy without immunodeficiency.

A case of the cerebellar form of progressive multifocal leukoencephalopathy (PML) without remarkable immune depression or immune deficiency is reported here. The patient was a 74-year-old-woman who had complications of chronic renal failure and renal anemia for several years. Seven months before her death she had symptoms of general fatigue, gait disturbance and articulation disorder. During her hospitalization period her neurological disorder gradually progressed irreversibly with failure of consciousness and she died of respiratory failure. She did not have remarkable clinical signs of immunodeficiency nor did she receive immunosuppressive therapy. Clinically she had not been diagnosed with PML. At the post-mortem examination different degrees of demyelination were observed in the brain white matter: diffuse and severe in the cerebellum, moderate and coalescent in the brainstem, and light and patchy in the cerebrum. JC virus antigen-positive cells were frequently observed in the demyelinated lesions in the cerebrum and sometimes observed in the brainstem, but were rarely found in the cerebellum. These findings suggest that PML lesions may be present with different degrees of demyelination that are inversely correlated with the number of JC virus-infected cells. This fact should be considered when evaluating the brain biopsies of PML patients.