[A case of chronic herpes encephalitis with myelodysplastic syndrome (MDS)].

A 72-year-old male suffering with MDS was admitted to our hospital because of slowly progressive dementia, convulsions and consciousness disturbance. A CT scan of the brain showed a low density area in the right temporal to parietal lobe and T2-weighted MRI of the brain revealed a high intensity signal in the same area. Herpes simplex virus DNA was detected in CSF by PCR method. He was diagnosed as having herpes simplex encephalitis but his clinical course was prolonged and considered atypical as herpetic infection in CNS. However, after administration of aciclovir, progression of his symptoms stopped, and a CT scan still revealed abnormal findings with the same area after more than four months. We thought his chronic course of herpes encephalitis was caused by incomplete immune function suppressed by MDS.