Phenotypic and Positron Emission Tomography with [18F]fluordeoxyglucose (FDG PET) differences in corticobasal syndrome: comparison of two cases.

Corticobasal syndrome (CBS) is a rare cause of dementia and comprises varied combinations of subcortical signs (akinetic-rigid parkinsonism, dystonia, or myoclonus) with cortical signs (apraxia, alien hand or cortical sensory deficit), usually asymmetric. We aimed to report and compare the clinical and neuroimaging presentation of two patients diagnosed with CBS. While case 1 had severe non-fluent aphasia associated with mild apraxia and limb rigidity, case 2 had a more posterior cognitive impairment, with a different language pattern associated with marked visuospatial errors and hemineglect. FDG PET played a significant role in diagnosis, suggesting, in the first case, corticobasal degeneration and, in the second, Alzheimer's disease pattern. CBS has been widely studied with the advent of new in vivo methods such as brain FDG PET. Studies that deepen the phenotypic and biomarker heterogeneity of CBS will be of great importance for better classification, prognosis, and treatment of the condition.