Diagnostic uncertainty of steroid-modified Marburg's variant of multiple sclerosis even at autopsy: A case suggesting lymphoma and related myelin loss.

MS (multiple sclerosis) has specific criteria to avoid misdiagnosis. However, the Marburg variant of MS is so fulminant that initial axonal damage and other atypical observations have been allowed in past reports. We present a 74-year-old autopsy case with a vanishing tumor after steroids and radiation therapy, which was pathologically diagnosed as a Marburg variant with initial axonal loss. The case displayed radiological lymphoma-like observations: mass effects protruding to the lateral ventricle, fused extension from the choroid plexus to white matter with C opening sign, a growing lesion from the skull dura mater, high in diffusion-weighted imaging and low in apparent diffusion coefficient on magnetic resonance imaging (MRI) suggesting high cell density lymphoma. In addition, clinical manifestations were atypical for MS: upper limb monoplegia without ipsilateral lower limb involvement, pleocytosis over 50 cells/μL, and class 3 cytological abnormality in cerebrospinal fluid. However, at autopsy following steroids and radiation therapy, there were no lymphoma-like lesions, such as mass effects, fused extensive lesions, masses on the skull dura mater, or high cell density lesions. Instead, there were only myelin losses corresponding to the MRI lesions, highlighting the potential for contamination by other diseases in steroid-modified Marburg's variant of multiple sclerosis, possibly due to lymphoma, even at autopsy.