Neuromyelitis Optica with Leukodystrophy-Like Features Resembling CADASIL

Background: Neuromyelitis optica spectrum disorders (NMOSD) encompass an autoimmune central nervous system (CNS) syndrome usually associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Severe attacks of optic neuritis and longitudinally extensive transverse myelitis (LETM) are characteristic, although uncommon patterns with more restricted or more extensive CNS involvement may occur. Here we aim to present the case of a patient with extensive brain white matter involvement resembling leukodystrophy as an uncommon MRI finding in NMOSD with AQP4-IgG and to review the literature in this context. Case Presentation: A 63 year-old woman who developed two episodes of optic neuritis in the right eye throughout the course of a year. Brain MRI showed bilateral, extensive and confluent involvement of white matter, resembling Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) or inherited leukodystrophies, none of which were confirmed by genetic testing. Further studies revealed patchy lesions along the spinal cord and positivity for AQP4-IgG. Thus, diagnostic criteria for NMOSD were met. Conclusions: A bilateral extensive white-matter involvement resembling leukodystrophy is an uncommon feature that must be considered as a potential radiological pattern of NMOSD in further studies.