A Case of Atypical Multiple Sclerosis Mimicking Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Syndrome.

It remains important to be able to distinguish between multiple sclerosis (MS) and cerebral autosomal dominant arteriopathy and subcortical ischemic leukoencephalopathy (CADASIL), although it has yet to be reported that MS and CADASIL can be seen together. We encountered a 63-year-old female patient compatible with MS in terms of clinical features but compatible with CADASIL in terms of brain magnetic resonance imaging (MRI) findings. Migraine, vascular dementia, and subcortical stroke events, which are among the classic clinical features of CADASIL, were not present. In the cerebrospinal fluid (CSF) examination, the oligoclonal band (OCB) was positive and the NOTCH 3 mutation was negative in the serum. The patient, whose initial symptom was optic neuritis, recovered with IV corticosteroids and azathioprine therapy. The patient's daughter and aunt had previously been diagnosed with MS. We present a case of MS mimicking CADASIL in terms of atypical demyelinating lesions.