Background

1. Juliana M. S. S. Amaral1, Natália C. Talim1, Lívia E. C. Talim1, Márcia Prates1, Rodrigo Kleinpaul1, Carolina R. Araujo1, Cristiane F. Rocha1, Kazuo Fujihara2, Douglas Sato2, Marco A. Lana-Peixoto1. 1CIEM MS Research Center, Federal University of Minas Gerais Medical School, Belo Horizonte, Brazil, and 2Tohoku University, Sendai, Japan. RELAPSING LONGITUDINALLY EXTENSIVE TRANSVERSE MYELITIS IN HUMAN T-LYMPHOTROPIC VIRUS TYPE 1-2 INFECTION severe paraparesis and dysesthesia in both legs. Spinal MRI disclosed severe atrophy of the spinal cord between its T1 – T10 vertebral segments. Brain MRI was unrevealing. Search for serum aquaporin 4-IgG by cell-based assay was negative, whereas ELISA detected HTLV I-II serum antibodies. Conclusion Veryrarely HAM/TSP maymanifest as relapsing LETM in previouslyhealthypatients. It hastobeincluded in thedifferentialdiagnosisofNMOSD, mainly in countries whereinfectionby HTLV-1 ishighlyprevalent. References: 1. Delgado SR, SheremataWA, Brown Adet al. Human T-lymphotropic virus type I or II (HTLV-I/II) associated with recurrent longitudinally extensive transverse myelitis (LETM): two case reports. J Neurovirol 2010; 16: 249-53. 2- Souza A, Tanajura D, Toledo-Cornell C, Santos S, et al. Immunopathogenesis and neurological manifestations associated to HTLV-1 infection. Rev Soc Bras Med Trop 2012; 45: 545-552. Figure. Spinal MRI.T2-weighted sequence showingspinalatrophyfrom T1 to T10. Background Neuromyelitisoptica spectrum disorders (NMOSD) are severe, inflammatory, immune-mediated disorders of the central nervous system which predominantly affect the optic nerves and the spinal cord. Longitudinally extensive transverse myelitis (LETM) is the most suggestive sign of NMOSD although it may occur in a number of other conditions. HTLV-1 infection has a worldwide distribution but is highly prevalent in Latin America, Middle East and Africa. Its associated myelopathy or tropical spastic paraparesis (HAM/TSP) is the most common neurological complication of the viral infection. HAM/TSP usually has a slow onset with chronic progression, but an acute and more severe form of the disease, characterized by rapid progression, may involve extensive length of the spinal cord with swelling and vacuolization mimicking the longitudinally extensive transverse myelitis (LETM) associated with anti-aquaporin-4 autoimmunity. Cases of LETM with rapid progressive course have been reported in post-transfusion and post-transplantation patients. We report a previously healthy anti-AQP4- IgGseronegative patient who developed relapsing LETM associated with HTLV-1 infection. Case report A 41-year-old mulattoe female, was in good health until 2004 when noticed slight weakness of the left lower limb. She denied any sensation or sphincter disturbance in association with the weakness. No work-up was done. She did well with no progression of her symptom until 2011 when she developed