LAUSR

Antibodies to myelin oligodendrocyte glycoprotein (MOGAbs) define a distinct entity of inflammatory CNS diseases, commonly presenting with subacute optic neuritis and/ or myelitis in adults and encephalomyelitis in children [5]. Patients with unilateral leptomeningeal enhancement, meningoencephalitis, and unilateral cortical FLAIR-hyperintense lesions have also been described and can present an atypical fulminant course [1]. Although guidelines suggest to analyse MOG-Abs in serum only, recent data support the additional diagnostic value of testing CSF in highly suggestive seronegative cases [4]. Scarce pathological brain evaluations confirmed the distinct entity of MOG-Abs-associated disorders (MOGAD), characterised by relative axonal sparing, perivenous, subpial, cortical and confluent primary demyelination, reactive gliosis, and inflammatory infiltrates predominantly constituted by granulocytes, macrophages, and CD4 + T cells [2, 3, 6]. We herein report the first autoptic findings of brain, spinal cord, nerve roots, and leptomeninges of a patient with MOGAbs positivity in CSF only. A 81-year-old man with a history of arterial hypertension presented with acute urinary retention requiring catheterisation, preceded by 7-day progressive lower limbs weakness. On neurological examination, lower limbs paraplegia with absent deep tendon reflexes and L1 sensory level loss were observed. Routine laboratory analyses were unremarkable. Spinal cord MRI showed multiple short T2-hyperintense lesions involving the spinal cord from the cranio-cervical junction to T12 and a central tumefactive lesion extending longitudinally from T9 to the conus (Fig. 2a–b). On T1 sequences and gadolinium administration, meningeal enhancement along the surface of frontal lobes, brainstem, cervical, and dorsal spinal cord were observed together with enhancement and thickening of all cranial nerves (expecially trigeminal roots) and lumbosacral nerve roots (Fig. 1a, b). CSF analysis revealed mild lymphocytic pleocytosis (29 cells/μL, NV < 8), increased protein content (5.16 g/L, NV < 0.45 g/L), CSF oligoclonal bands (type 3 pattern) and an increase of the albumin quotient (10.33, NV < 7) and IgG index (0.72, NV < 0.7). Analyses for a broad range of viruses and bacteria, flow cytometry, and clonal B‐cells populations yielded negative results, thus excluding infectious or haematological conditions. Fixed cell-based and immunoblot assays (Euroimmun, Lübeck) excluded the presence of anti-neuronal (Hu, Yo, Ri, Tr, GAD65, CV2/ CRMP5, Ma2, SOX1, Amphiphysin, NMDAR, LGI1, CASPR2, AMPAR1/2, GABAbR, and DPPX) antibodies. Anti-AQP4 and anti-MOG antibodies analysed with fixed cell-based assay (Euroimmun, Lübeck) resulted also negative. Whole-body computed axial tomography did not show any malignancies nor lymphadenopathy. MOG-Abs analysed with live cell-based immunofluorescence assay confirmed in two different reference laboratories (Verona and Innsbruck) * Sara Mariotto [email protected]