Dementia characterized by abundant neurofibrillary tangles and scarce senile plaques: a quantitative pathological study.

We report an elderly case who had demonstrated progressive memory disturbance and disorientation for 4 years. The clinical features were indistinguishable from late-onset dementia of the Alzheimer type (DAT). Neuropathologically, however, senile plaques (SPs) were almost absent throughout the brain. In contrast, numerous neurofibrillary tangles (NFTs) were observed in the hippocampus and neighboring regions, with much higher density than age-matched normal controls. The immunohistochemical and ultrastructural properties of the NFTs were identical to those of typical DAT. The present case is histologically different from DAT because of the scarce SPs and indicates that numerous NFTs in the hippocampal region can be formed independently of the existence of SPs.