Chimeric antigen receptor (CAR) T cell therapy has revolutionized the care of patients with relapsed/refractory large B cell lymphoma and is associated with unique toxicities, in particular cytokine release syndrome (CRS) and neurotoxicity/immune effector cell‐associated encephalopathy syndrome (ICANS). However, transverse myelitis following CAR T therapy was rarely reported.

We report a 29-year-old woman with diffuse large B cell lymphoma who received anti-CD19 CAR T-Cell therapy after lymphodepletion with Fludarabine and Cytoxan, presented initially with fever and dyspnea consistent with CRS and treated with Tocilizumab. The patient became aphasic transiently and unable to follow commands on day 5 and treated with corticosteroid for high grade ICANS. Her hospital course was further complicated by progressive weakness in bilateral lower extremities after CAR T therapy. Neurological examination showed hyperreflexia, quadriparesis (more severe in legs), and sensory level in lower cervical region and impaired proprioception in lower extremities. Brain and spine MRI with and without contrast showed evidence of expansible heterogenous non-enhancing T2/FLAIR hyperintensity within medulla extending inferiorly into the cervical and thoracic cord. CSF analysis revealed mild pleocytosis, but negative results for cytology and microbiology including viral meningoencephalitis panel. Aquaporine-4, anti MOG and paraneoplastic autoantibodies from serum were unremarkable.  She was treated with high dose steroids, IVIG and plasma exchange over the several days of admission. Repeated spine MRI after one month showed significant improvement of medullary and spinal T2 hyperintensities while there was only a partial improvement in her symptoms after 4 months.

We describe an unusual case of transverse myelitis extending from medulla into the cervical and upper thoracic cord after treatment with anti‐CD19 CAR T cell therapy. To the best of our knowledge, only a few cases of transverse myelitis have been reported after CAT T therapy and none of them were associated with brainstem involvement.