Editing Transverse myelitis (section)

===Longitudinally extensive transverse myelitis===
A proposed special clinical presentation is the "longitudinally extensive transverse myelitis" (LETM), which is defined as a TM with a spinal cord lesion that extends over three or more vertebral segments.<ref>{{Cite journal |vauthors=Cuello JP, Romero J, de Ory F, de Andrés C |date=September 2013 |title=Longitudinally extensive varicella-zoster virus myelitis in a patient with multiple sclerosis |journal=Spine |volume=38 |issue=20 |pages=E1282–E1284 |doi=10.1097/BRS.0b013e31829ecb98 |pmid=23759816 |s2cid=205519782}}</ref> The causes of LETM are also heterogeneous<ref name="pmid26209588">{{Cite journal |display-authors=6 |vauthors=Pekcevik Y, Mitchell CH, Mealy MA, Orman G, Lee IH, Newsome SD, Thompson CB, Pardo CA, Calabresi PA, Levy M, Izbudak I |date=March 2016 |title=Differentiating neuromyelitis optica from other causes of longitudinally extensive transverse myelitis on spinal magnetic resonance imaging |journal=Multiple Sclerosis |volume=22 |issue=3 |pages=302–311 |doi=10.1177/1352458515591069 |pmc=4797654 |pmid=26209588}}</ref> and the presence of [[myelin oligodendrocyte glycoprotein|MOG]] auto-antibodies has been proposed as a diagnostic biomarker.<ref name="pmid26209592">{{Cite journal |display-authors=6 |vauthors=Cobo-Calvo Á, Sepúlveda M, Bernard-Valnet R, Ruiz A, Brassat D, Martínez-Yélamos S, Saiz A, Marignier R |date=March 2016 |title=Antibodies to myelin oligodendrocyte glycoprotein in aquaporin 4 antibody seronegative longitudinally extensive transverse myelitis: Clinical and prognostic implications |journal=Multiple Sclerosis |volume=22 |issue=3 |pages=312–319 |doi=10.1177/1352458515591071 |pmid=26209592 |s2cid=8356201}}</ref>