Neurofibrillary tangle predominant form of senile dementia of Alzheimer type: a rare subtype in very old subjects.

In a consecutive autopsy series of 580 demented elderly subjects, 256 with the clinical diagnosis of probable/possible Alzheimer's disease (AD), there were 10 cases aged between 80 and 99 years with moderate to severe dementia or confusional state in which neuropathological studies revealed abundant neurofibrillary tangles with predominant involvement of the allocortex (entorhinal region, subiculum, CA 1 sector of hippocampus, amygdala) but no or only very few senile plaques. Small numbers of diffuse deposits of beta A4 amyloid protein were present in the entorhinal cortex of 3 and in the isocortex of 5 brains, while neuritic plaques were totally absent. Only a few cases of this "senile dementia with tangles only" or, more correctly, "neurofibrillary predominant type of AD" corresponding to the limbic stage of neuritic AD pathology have been described in the literature. This rare subtype occurring in very old (over 80 years of age) subjects that does not fall within the currently used neuropathological criteria for diagnosis of AD warrants further clinico-pathological documentation.