Entorhinal neurofibrillary tangles in Alzheimer disease with Lewy bodies.

Entorhinal cortex is the major source of hippocampal afferents. Its neurons, especially in layer 2, develop neurofibrillary tangles (NFTs) in Alzheimer disease (AD). We quantified entorhinal NFTs in cases of AD, elderly controls, and in brains with both AD pathology and subcortical and neocortical Lewy bodies, (a Lewy body variant, LBV). A nosologic controversy hinges on whether LBVs are a form of AD or a different disease, since they have few neocortical NFTs and their neuritic plaques often lack paired helical filament immunoreactivity. The LBVs had more entorhinal NFTs than controls (P less than 0.001), but fewer than ADs (P less than 0.02), despite comparable numbers of neuritic plaques. AD pathology in LBVs is of moderate severity, or perhaps in an earlier developmental stage.