121. Tumefactive Myelin Oligodendrocyte-Associated Disease Presenting as Acute Flaccid Myelitis: A Case Report

• Published in: Multiple sclerosis and related disorders 2024-12, Vol.92
• Main Authors: Haroun, Lynda, Ahmed, Hakim Si, Daoudi, Smail
• Format: Article
• Language: English
• ISSN: 2211-0348
• DOI: 10.1016/j.msard.2024.106082

Myelin oligodendrocyte-associated disease (MOGAD) is an inflammatory disorder targeting the central nervous system, particularly the optic nerve and the spinal cord. Tumefactive demyelination is reported in approximately one fifth of the cases of MOGAD. Transverse myelitis is one of the most common presentations of MOGAD. Acute flaccid myelitis is a different entity; it is associated with viral infections, is more common in children, and is characterized by the rapid onset of limb weakness with areflexia. There have been a few reported cases of MOGAD mimicking acute flaccid myelitis. We report a similar case with the characteristic of being a tumefactive form. A 14-year-old girl presented to the emergency department with rapidly progressive muscle weakness in both lower limbs, hypotonia, areflexia, and complete anesthesia, associated with urinary and fecal incontinence. The medical history revealed that the patient had jaundice a few weeks prior, which occurred during a school outbreak and had resolved itself without treatment. The magnetic resonance imaging (MRI) showed two tumefactive lesions in the brain, one longitudinally extensive in the thoracic spinal cord and one in the conus medullaris. The lesions were hyperintense in T2 and FLAIR, hypointense in T1, with gadolinium enhancement and edema. Laboratory tests, including lumbar puncture, showed no signs of infection; however, there was a slight increase in the hepatic enzymes. Additional screening for human immunodeficiency virus (HIV), hepatitis viruses A,B, and C, syphilis, tuberculosis, brucellosis, and Lyme disease had all been negative. The anti-MOG antibodies were positive. The patient received anti-inflammatory treatment including steroids, plasma exchange, and immunoglobulin, with a slight clinical improvement. The clinical presentation of our patient is highly suggestive of acute flaccid myelitis: the rapid onset of symptoms, the age of the patient, the severity of the weakness, the areflexia, the medical history of viral infection, and the poor response to steroids and plasma exchange. However, the presence of tumefactive brain lesions and the lesion in the conus medullaris argue against this diagnosis and support MOGAD; the presence of anti-MOG antibodies confirms the diagnosis. The patient was put on anti-interleukin 6 treatment with no signs of relapse in the last 6 months. Although acute flaccid myelitis is not the most common presentation of MOGAD, it is important to keep this diagnosi