LAUSR

1174 Myelin ol igodendrocyte glycoprotein‐associated disorder (MOGAD) is an autoimmune oligodendrocytopathy, whereas neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy. Both cause central nervous system demyelination, and serum IgG‐MOG and anti‐aquaporin‐4 antibodies serve as their respective biomarkers. Both these disorders, although distinct, share common clinical features, such as optic neuritis and myelitis. There are rare reports (0.05%) of concomitant occurrence of these otherwise distinct disorders,[1] and we present one such rare occurrence in a woman who presented with left hemiparesis and persistent hiccups. Magnetic resonance imaging (MRI) brain revealed a tumefactive demyelinating lesion involving the right temporal lobe, lentiform nucleus, and cerebral peduncle, and another small lesion in the area postrema. Both these lesions showed patchy contrast enhancement [Figure 1]. MRI spine was normal. A possibility of NMOSD was kept and serum was tested for antibodies against aquaporin‐4 and myelin oligodendrocyte glycoprotein (cell‐based assay), both of which were strongly positive (tested twice). A diagnosis of concomitant NMOSD and MOGAD was made, and she was treated with intravenous methylprednisolone pulse (1 g daily for 5 days), followed by plasma exchange (5 cycles done on alternate days) with some symptomatic improvement (left upper and lower limb power 3/5 on Medical Research Council (MRC)). Thereafter, she was treated with rituximab infusion (1 g) with next dose planned after 2 weeks and discharged on tapering steroids. Dual‐positive patients tend to have a multiphasic disease course, higher relapse rates, and more disability and should be aggressively managed.[2] NMOSD and MOGAD Dual Positivity: An Extremely Rare Phenomenon