A 45-years old unconscious woman was admitted to the hospital, where she died 3 days later. For the preceding month she had suffered from a headache. She had no past medical history. Cerebrospinal fluid pressure was increased, there were 350 mg/100 of protein, and 105 mg/100 of glucose. Neuropathological examination revealed that the main microscopic abnormality was massive accumulation of PAS-positive polyglucosan bodies (PB) in the cerebral hemispheres, brain stem and cerebellum. These bodies were found most frequently around the vessels, or diffusely in the nervous tissue beneath the pia, particularly in depth of the cortical sulci. They were observed in the processes of nerve cells, astrocytes, and microglia cells. The material stored in PB was strongly positive in PAS, and PAS-dimedone, weakly stained in H&E, the reaction to GFAP, RCA-1 and Bielschowsky methods appeared rather on PB periphery. The neuropathologic features are consistent with adult polyglucosan body disease and are distinctive from other conditions in which PB may accumulate.