Case of posterior cortical atrophy (PCA) evolved to PCA-CBS

A 68-year-old lawyer developed insidious disturbances in topographic orientation and apraxia. He underwent a geriatric evaluation, only documenting slight cognitive disturbances, and a 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), showing mild right-lateralised frontoparietal hypometabolism. After 1 year, because of worsening in spatial orientation and the onset of dressing apraxia, he was referred to our memory clinic. The neuropsychological evaluation documented proeminent visuospatial, praxis deficits and dysgraphia. Cerebrospinal fluid biomarker analysis showed mild increase of total-τ, with normal Aβ1-42, ruling out Alzheimer's disease. Progression of the right parietal hypometabolism at FDG-PET and right superior longitudinal fasciculus damage at high-field MRI revealed a probable neurodegenerative aetiology. The neurological examination disclosed then Gerstmann's and Balint's syndromes, and extrapyramidal signs later appeared, suggesting the diagnosis of posterior cortical atrophy associated with corticobasal syndrome. Genetic analysis for mutations inmicrotubule-associated protein tau (MAPT), C9orf72 and GRN genes was negative. A 1-year follow-up documented significant worsening of the cognitive and functional impairment, revealing a frank dementia.