[Frontal variant of Alzheimer's disease. Two pathologically confirmed cases and a literature review].

Introduction: Alzheimer's disease (AD) is the most frequent degenerative dementia in our setting. In most patients the initial manifestations of the disease consist in a selective and progressive compromise of memory. Yet, it is not a homogeneous process and in some cases the mode of presentation can be atypical. The presentation of AD in the form of an early disorder affecting personality, behaviour and the executive functions has been called the frontal variant of AD. In our case, its definitive diagnosis was only possible by means of a histological analysis, given the fact that the applicable clinical criteria were then insufficient to reach a diagnosis of this atypical form of AD.

Case Reports: We report the cases of two patients, one female and one male aged 60 and 52 respectively, who presented a progressive picture of cognitive impairment with initial involvement of the executive functions and personality changes, together with mood disorders. As a result, the initial diagnosis was one of probable frontotemporal dementia. However, in both cases, the autopsy revealed data consistent with a diagnosis of AD, with a distribution of the pathology that essentially affected the frontal lobes.

Conclusions: AD has a heterogeneous form of presentation, which can give rise to errors in its initial diagnosis, since current clinical criteria do not take this clinical variability sufficiently into account. We therefore consider it important to pay attention to the atypical forms of AD with the aim of developing new diagnostic methods that allow AD to be distinguished from other degenerative processes.