Pattern of brexucabtagene autoleucel-related neurotoxicity on magnetic resonance imaging of the brain in a patient with relapsed/refractory B-cell acute lymphoblastic leukemia and prior leptomeningeal disease.

Immune effector cell-associated neurotoxicity syndrome (ICANS) secondary to chimeric antigen receptor T-cell therapy is common in adult patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (ALL), but imaging findings during neurologic toxicity and their meaning have yet to be systematically described in this patient population. Brexucabtagene autoleucel (brexu-cel) is a CD19-directed autologous T-cell immunotherapy for the treatment of adult patients with R/R B-cell ALL that can enter the central nervous system. We present a case of an adult patient with R/R B-cell ALL and prior leptomeningeal disease who developed neurologic toxicity and new findings on magnetic resonance imaging of the brain while receiving brexu-cel. We interpret the patient's neuroimaging studies within clinical context to differentiate ICANS from active treatment of residual leukemia.