Postpartum neurological mystery: a case report of tumefactive multiple sclerosis mimicking intracranial neoplasm in a lactating woman.

Introduction and Importance: Tumefactive multiple sclerosis (TMS) is a rare and severe variant of MS, characterized by large, tumor-like demyelinating lesions in the central nervous system. It can present abruptly with diverse neurological symptoms, including motor deficits, seizures, visual disturbances, and speech or swallowing difficulties. Immune modulation during pregnancy and lactation may trigger or exacerbate demyelinating episodes. Radiologically, TMS often mimics neoplastic or infectious lesions, posing diagnostic challenges, particularly in regions endemic for infections such as tuberculosis. Case Presentation: A 32-year-old lactating woman presented with acute dysphagia and dysphonia. Brain magnetic resonance imaging (MRI) revealed multiple intracranial lesions initially suggestive of infection or neoplasm. Breastfeeding was discontinued, and the infant transitioned to formula feeding. Empirical antitubercular therapy was initiated, but a stereotactic biopsy confirmed TMS. The patient was treated with high-dose corticosteroids and rituximab, resulting in marked clinical improvement. Follow-up MRI at 3 months demonstrated near-complete resolution of the lesions. Discussion: TMS is a rare demyelinating condition that can closely mimic intracranial tumors or infections, often leading to delayed or inappropriate management. In postpartum women, immune system shifts may precipitate demyelinating episodes. Early histopathological confirmation is critical to guide appropriate therapy, prevent unnecessary interventions, and optimize outcomes. This case highlights the importance of considering TMS in atypical postpartum neurological presentations. Conclusion: TMS should be included in the differential diagnosis of mass-like brain lesions in postpartum women. Histopathological confirmation enables accurate diagnosis and timely initiation of immunotherapy, improving clinical and radiological outcomes.