Objective:

To present a case of a patient with coexisting multiple sclerosis and neuropsychiatric systemic lupus erythematosus, initially misdiagnosed with depression.

Approach:

• Patient Presentation: A 69-year-old female presented with persistent depressive symptoms, later developing gait instability and cognitive decline.
• Diagnostic Evaluation: Comprehensive clinical and laboratory evaluations, including MRI and serological tests, were conducted to establish the diagnosis.
• Treatment: The patient was treated with glucocorticoids and hydroxychloroquine, alongside continued psychiatric care.

Key Findings:

• Initial misdiagnosis of major depressive disorder led to a delay in appropriate treatment.
• Brain MRI revealed multifocal white matter lesions consistent with demyelination.
• Serological tests showed positivity for various autoantibodies, including ANA, anti-dsDNA, and others, confirming the diagnosis of MS and NPSLE.

Interpretation:

This case illustrates the diagnostic challenges of overlapping autoimmune CNS disorders and the necessity for thorough longitudinal assessment.

Limitations:

• The patient was initially treated for depression without autoimmune evaluations.
• The presence of MOG-IgG may represent a false-positive result.

Conclusion:

The patient demonstrated clinical improvement following treatment.