Oligodendrocytes within astrocytes ("emperipolesis") in the cerebral white matter in hepatic and hypoglycemic encephalopathy

We report the occurrence of oligodendrocytes within astrocytes ("emperipolesis") in two autopsy cases of metabolic encephalopathy: one patient with hepatic encephalopathy due to citrullinemia who suffered recurrent unconsciousness (clinical duration, 32 months) and another with hypoglycemic encephalopathy who lapsed into a persistent vegetative state (clinical duration, 22 months). In both cases, hypertrophic astrocytes were found to have engulfed one to several oligodendrocytes in the devastated cerebral white matter. Previous studies have reported that emperipolesis occurs in various CNS diseases showing destruction of myelin or inflammation of the white matter, including multiple sclerosis, cerebral infarct and CJD. The present findings suggest that emperipolesis can occur even in chronic metabolic disorders that extensively involve the cerebral white matter.