Conus medullaris syndrome as a presenting feature of MOG-associated disease.

We report a case of conus medullaris syndrome presenting with lower limb and bladder symptoms. MR imaging showed an abnormality in the lowest part of the spinal cord as a first presentation of myelin oligodendrocyte glycoprotein (MOG)-associated disease. While such cord swelling can mimic a tumour, these patients respond well to corticosteroids, with good outcomes. MOG-associated disease is an immune-mediated syndrome distinct from aquaporin 4 antibody positive neuromyelitis optica syndrome and is now considered an independent entity. Although there can be overlapping phenotypes, there are also differences, and MOG-associated disease generally has a much better prognosis compared with aquaporin 4 antibody-positive neuromyelitis optica syndrome.