A Case of Personality and Behavioral Changes with Frontotemporal and Cerebellar Atrophy on MRI with Corresponding Hypometabolism on FDG-PET

The differential diagnosis of a patient with cognitive, behavioral, and motor symptoms is broad. There is much overlap between neurocognitive disorders due to frontotemporal dementia and other subcortical dementia. A less known diagnosis, cerebellar cognitive affective syndrome (CCAS), should also be considered. . A 29-year-old female presented with ataxia and left-sided weakness. CSF showed oligoclonal bands, and MRI showed multiple white matter lesions with some atrophy. She was diagnosed with multiple sclerosis (MS). At age 35, she developed frontal lobe symptoms and executive dysfunction; she was diagnosed with MS with bipolar disorder. Neuropsychological evaluation at that time showed significant deficits in multiple cognitive domains. Subsequent MRI showed progressive frontotemporal atrophy, and FDG-PET uncovered hypometabolism in the frontotemporal lobes and cerebellum. At age 38, her behavior worsened with aggression, and she was started on olanzapine. She responded well with decreased agitation and improved motivation and attention. Compared with previous scans, most recent MRI and FDG-PET showed interval increase in cerebellar atrophy with increase in hypometabolism in the cerebellum, respectively. Based on cerebellar, affective, and subcortical cognitive examination findings, our diagnosis is probable CCAS. The cerebellum should be considered as a possible etiology of frontal subcortical cognitive impairment.