Kertesz A et al. The Evolution and Pathology of Frontotemporal dementia Brain 2005 128;1996-2005
Pathology varies. It can include balloon neurons (corticobasal ganglionic degenerations), microtubular tau (50%) and inclusions that are tau negative and ubiquitin positive (50-60 %) also called MND type inclusions. Another group lacks the above and are called dementia lacking distinctive histology. Pick disease has ntracytoplasmic neuronal inclusions, Pick bodies with specific staining in tau in the fascia dentata, hippocampus and cortex.
The clinical phenotypes are FTD-BV (behavioral variant) with loss of behavior and personality; PPA (primary progressive aphasia) with anomia, logopenia and nonfluent speech; corticobasal ganglionic degeneration with unilateral rigidity, apraxia/alien hand and late cognitive change; PSP with vertical gaze palsy, axial rigidity and pseudobulbar palsy with overlap syndromes also.
Of 60 autopsied, 32 had FTD BV, 22 had PPA, 4 had CBGD, 2 had PSP; autopsies however showed MND type inclusions in 18, CBGD in 12, PSP in 3 , Picks in 6, and DLDH in in 6, AD in 10, 5 others showing 1 each of LBD/AD, LBD, Binswanger's d, GSS, and undetermined.
Tau negative pathologies were most likely MND type inclusions, DLDH, and presented with FTD-BV. But PPA, CBGD and semantic dementia appeared.
Tau positive pathology appeared in CBGD, PSP and Picks and presented with PPA CBDS or PSP