Creutzfeldt-Jakob disease with intranuclear vacuolar inclusions: a biopsy case of negative light microscopic findings and successful animal transmission.

In a 53-year-old man with a progressive mental deterioration and myoclonic jerks, brain biopsy failed to show any significant light microscopical findings. Electron microscopy revealed membrane-bound vacuolar inclusions in many neuronal nuclei as the only prominent finding. Hamsters intracerebrally inoculated with the biopsy material demonstrated typical spongiform changes in the gray structures of the brain when sacrificed on the 309th and 332nd days post inoculation, characteristic of experimental Creutzfeldt-Jakob disease (CJD). These intranuclear vacuolar inclusions, originally reported in experimental Creutzfeldt-Jakob disease in this laboratory, may be a valuable electron microscopic feature in some CJD cases and may play an important role in supporting the diagnosis of CJD.