Coexisting myelin oligodendrocyte glycoprotein antibody-associated disease and spinal dural arteriovenous fistula: A diagnostic and neuroimmunological challenge.

Central demyelinating disorders, notably myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), exhibit diverse clinical and radiological manifestations, thereby complicating accurate diagnosis. We present the case of a 78-year-old female patient who developed progressively worsening bilateral lower limb numbness and weakness, accompanied by fecal incontinence over a two-month period. Spinal MRI identified a longitudinally extensive lesion within the spinal cord, and serological analysis revealed MOG antibodies at a titer of 1:100. The patient experienced partial clinical improvement following glucocorticoid treatment, with no further neurological decline. Nevertheless, subsequent spinal magnetic resonance angiography uncovered a spinal arteriovenous malformation. This case underscores the potential diagnostic overlap between demyelinating and vascular myelopathies and highlights that partial responsiveness to steroids and the presence of specific antibodies do not preclude concurrent vascular pathology. Therefore, comprehensive diagnostic assessment, including vascular imaging, is warranted in patients exhibiting atypical or progressive myelopathy despite evidence suggestive of immune-mediated disease. These observations emphasize the clinical heterogeneity inherent to central demyelinating disorders and contribute valuable insights into the neuroimmunological and diagnostic challenges associated with such conditions.