Parkinson's disease and dementia with neuronal inclusions in the cerebral cortex: Lewy bodies or Pick bodies.

Cortical Lewy bodies may be difficult to differentiate from Pick bodies by the usual staining methods. This problem is illustrated in a case of progressive dementia with parkinsonian features. Lewy bodies were found, not only in the pigmented nuclei in the brainstem and in the cerebral cortex, but also in the dentate fascia, a predilection site for Pick bodies. The inclusion bodies were compared with the inclusion bodies in a case of Pick's disease. Intense argyrophilia of the cortical inclusion bodies argued in favor of Pick bodies; antibodies to phosphorylated neurofilaments reacted with the cortical inclusions and with classical Pick bodies, but antibodies to paired helical filaments reacted only with the Pick bodies. The most convincing evidence, that the inclusions were Lewy bodies, was obtained by electron microscopy. The filaments in the inclusions showed fuzzy deposits of electron dense material, characteristic for filaments of Lewy bodies. This contrasted with the smooth filaments of the Pick bodies. It is concluded that cortical inclusions in brains from patients with Lewy bodies in the pigmented nuclei of the brainstem most likely represent Lewy bodies. This can be confirmed by examining the ultrastructure of the inclusions.