A first report of progressive multifocal leukoencephalopathy in childhood-onset NMOSD.

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) has not been reported in pediatric neuromyelitis optica spectrum disorder (NMOSD) and rarely described in children.

OBJECTIVES

To report a case of PML in childhood-onset NMOSD.

METHODS

A single retrospective case report.

RESULTS

Nine years after diagnosis of aquaporin-4 antibody positive NMOSD, a 17-year-old boy treated with rituximab presented with painless right visual loss over 6 weeks coinciding with CD19 repopulation. Acute relapse treatment was given but he continued to deteriorate, and JC virus was detected in cerebrospinal fluid confirming PML.

CONCLUSION

PML can occur in childhood-onset NMOSD and protracted clinical presentations with unusual radiological features should prompt JCV testing. Balancing effective immunosuppression while mitigating the risks of associated complications in long-term relapsing conditions remains a challenge.