Treatment-resistant inflammatory demyelinating pseudotumor with Marburg-like features: A narrative review-based...

Inflammatory demyelinating pseudotumor (IDP) mimics intracranial neoplasms in terms of both clinical presentation and imaging features. IDP with Marburg-like features represents a severe form of inflammatory demyelinating encephalomyelitis, marked by a dramatic onset, aggressive course, absence of remission, and the presence of tumor-like central nervous system demyelinating lesions. Key features of IDP in brain magnetic resonance imaging include open or incomplete ring enhancement, low T2 rim, peripheral diffusion restriction, absent or mild mass effect, and perilesional edema. In brain magnetic resonance spectroscopy (MRS), elevated glutamate, choline, and lactate peaks are observed; however, brain MRS findings can be nonspecific and nondifferentiating. Pathologic findings show prominent perivascular lymphoid infiltrates consisting predominantly of leukocyte common antigen (LCA)+ and PAX5+ B lymphocytes in immunohistochemistry staining, parenchymal and perivascular macrophages (CD68+), some with visible myelin globules on Luxol Fast Blue staining, preferential loss of myelin with relative axonal preservation and the formation of axonal spheroids (swellings), reactive astrocytosis (GFAP+ and ATRX-), and remyelination with thinner myelin sheaths than background axons at the periphery of the plaque. A review of previous case reports revealed that prompt aggressive immunosuppression therapy in the IDP with Marburg-like features may lead to a favorable response. Initiating treatment with a cycle of high-dose corticosteroids followed by rescue immunosuppressive therapy using cyclophosphamide, mitoxantrone, rituximab, or alemtuzumab demonstrated positive outcomes. In addition, maintenance immunosuppressive therapy with B-cell-depleting agents, such as rituximab and ocrelizumab, showed potential for controlling disease activity and improving long-term prognosis.