Tumefactive Demyelinating Lesion Induced by Infliximab in a Patient With Rheumatoid Arthritis: A Case Report.

Tumor Necrosis Factor-alpha (TNF-α) inhibitors have been successfully used to treat rheumatoid arthritis (RA), psoriatic and ankylosing arthritis, and inflammatory bowel disease. While these inhibitors effectively decrease the inflammatory activity of immune-related disorders, they have been associated with central nervous system (CNS) and peripheral demyelination. In this study, we report a 44-year-old female patient with RA who developed neurological symptoms after a course of infliximab therapy due to tumefactive demyelinating lesions (TDLs). Imaging findings led to discontinuation of the drug and treatment with corticosteroids, resulting in clinical improvement. This case underscores the importance of monitoring neurological side effects during TNF-α therapy and early intervention when symptoms occur. Tumor necrosis factor-alpha inhibitors, such as infliximab, can unmask or induce demyelinating lesions, even in patients without prior multiple sclerosis. Prompt MRI evaluation and infliximab discontinuation, followed by corticosteroids, can lead to clinical improvement. Neurological assessment is recommended before initiating TNF-α inhibitors, especially in patients with risk factors for demyelination.