Abstract
Idiopathic inflammatory-demyelinating diseases are a wide-ranging group of central nervous system disorders extending from the most common relapsing-remitting and secondary progressive forms of multiple sclerosis (MS) to the least common fulminant or acute IIDDs, such as the Marburg variant of multiple sclerosis, Balo's concentric sclerosis, and Schilder's disease. There exist typical and atypical clinical, laboratory, imaging, and pathological procedures and findings that will help in the appropriate distinction of various IIDDs, but errors and uncertainties in diagnoses are still common due to the existence of significant similarities in some if not all diseases under the spectrum of IIDDs.
These diseases may be insignificant and uncommon as individual disease entities but they are important to be ruled out before diagnosing other common acute severe demyelinating conditions such as MS and tumor-like lesions. Serving as important differential diagnoses, unique clinical, imaging, neuroradiological features, and immunological biomarkers can be used for their differentiation from classical MS, which also helps in discovering patients with rarer disorders with a high risk of disability progression.