Corticobasal syndrome mimicking Foix-Chavany-Marie syndrome with suggested 4-repeat tauopathy by tau PET.

We hereby present an atypical case of CBS showing clinical features mimicking FCMS at first presentation. TDP-43 proteinopathy was suspected based on the clinical symptoms in the early stages of the disease; however, the clinical course and imaging findings including tau PET suggested that her pathological background was 4-repeat tauopathy.