Atypical Demyelinating Disorders: MR Imaging Features, Atypical Triggers, and Etiopathogenesis

Abstract

Atypical demyelinating lesions (ADLs) can be idiopathic, occurring as isolated and self-limited events, or can appear in different stages of relapsing demyelinating diseases. Not infrequently, ADLs occur in inflammatory syndromes associated with exogenous or endogenous toxic factors, metabolic imbalance, or infectious agents. It is important to recognize imaging patterns that indicate an inflammatory/demyelinating substrate in central nervous system lesions and to investigate potential triggers or complicating factors that might be associated. The prognostic and treatment strategies of ADLs are influenced by the underlying etiopathogenesis.

Keywords: Atypical demyelinating lesions; Cytotoxic lesions of the corpus callosus; Immune reconstitution syndromes; Multiple sclerosis; Osmotic myelinolysis; Toxic leukoencephalopathy; Viral-induced demyelination.