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 ɛ3/ ɛ4 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.