The clinical manifestation of frontal-variant Alzheimer's disease (fvAD) is not typical,and it is difficult yet necessary to differentiate fvAD from frontal-variant frontal temporal dementia (fvFTD).We describe a patient with early-onset Alzheimer's disease (AD) who presented with an fvFTD-like syndrome and apolipoprotein E ε3/ε4 genotype.A brain amyloid imaging procedure,11C-Pittsburgh compound B positron emission tomography (PET),supported the final diagnosis of AD.Our present case highlights the clinical variability that characterises early-onset AD.A multimodal approach is crucial when assessing rare forms of dementia.