Treatment-resistant Inflammatory Demyelinating Pseudotumor with Marburg-Like Features: A Rare Case Report.

Inflammatory demyelinating pseudotumors (IDPs), also known as tumor-like demyelinating lesions, are rare conditions that mimic intracranial neoplasms, presenting significant diagnostic challenges. The Marburg variant of multiple sclerosis (MS), an aggressive form of demyelinating disease, can present with IDP, further complicating diagnosis. We report the case of a 51-year-old male who developed progressive neurological deficits over one month. Brain MRI revealed bilateral supra- and infratentorial lesions, initially raising suspicion of both demyelinating disease and neoplastic processes. Extensive investigations, including spinal MRI, cerebrospinal fluid (CSF) analysis, and stereotactic biopsy, confirmed a diagnosis of IDP with Marburg-like features. Although initial improvement was achieved by high-dose corticosteroids and plasma exchange, the patient was worsened. The patient was a candidate for high-dose cyclophosphamide. This case underscores the importance of distinguishing IDP from aggressive demyelinating diseases such as Marburg MS, emphasizing the role of biopsy for definitive diagnosis and the critical need for prompt aggressive immunosuppressive therapy. Ultimately, the patient did not consent to initiating the cyclophosphamide pulse and left the hospital against medical advice. Unfortunately, the patient passed away approximately one month later.