Two patients, aged 59 and 73 years, presented with the clinical syndrome of Posterior Cortical Dementia (PCD). Follow-up during 3 and 11 years confirmed the progressive nature of the disorder. Posterior cerebral impairment was seen on SPECT studies. Neuroimaging studies showed an early dilatation of the right occipital ventricular horn which predominated over the cortical atrophy. This kind of cerebral atrophy could identify a subset of PCD cases that may be unrelated to Alzheimer's disease.