Frontotemporal dementia: a clinical-pathological study.

We report a 44-year-old female patient without any familial history of dementia presenting with increasing disturbances in behaviour and language followed by a progressive cognitive deterioration. Neuropsychological evaluation revealed a significant impairment on frontal lobe tests. A brain PET scan disclosed a severe frontal hypometabolism. The tentative diagnosis of frontotemporal dementia was made. Her condition rapidly worsened and she died 2 years after the beginning of her disease. Gross examination of the brain showed a selective symmetrical atrophy of both frontal and anterior part of the temporal lobes. Microscopical examination revealed severe neuronal loss in the frontal and anterior temporal cortex associated with gliosis and microvascular spongiosis in the superficial cortical layers in the absence of any specific neuronal or glial inclusions. These neuropathological findings were consistent with the diagnosis of dementia lacking distinctive histology. We discuss the nosology of the frontotemporal dementias, the diagnostic value of PET scan, the recent genetical developments which strongly support the pathogenic role of tau and we emphasize the importance of immunohistochemical examination for a definite neuropathological diagnosis.