Dementia is a major worldwide public health concern in view of the global ageing phenomenon. Dementia usually occurs in old age. However, if the symptoms occur in young patients, the diagnosis can be challenging. Posterior cortical atrophy is a variant of the Alzheimer’s disease, which is described as a presenile disease affecting relatively late-middleaged patients. A combination of clinical, neuropsychological, and neuroimaging techniques may facilitate making a diagnosis of this particular patient group, as demonstrated in this report. Although there is no effective disease-modifying agent for treating these patients to date, there may be considerable pressure to arrive at a quick and accurate diagnosis from the perspective of employment and insurance.