Recurrent dysphasia due to nivolumab-induced encephalopathy with presence of Hu autoantibody.

A 58-year-old man was being treated for squamous non-small-cell lung cancer with nivolumab. At the 17th of biweekly administrations he presented with global dysphasia, dysarthria and myoclonus in the right upper extremity. MRI showed multiple T2/FLAIR hyperintense lesions in the left hemisphere; lumbar puncture showed lymphocytic pleiocytosis in the CSF without identifiable pathogens. Hu antibodies were present in serum and CSF. Nivolumab was discontinued and corticosteroids were administered. The neurological symptoms gradually improved; MRI showed complete remission of cerebral lesions. After rechallenge with nivolumab his symptoms and cerebral lesions recurred, proving the causal relationship with nivolumab. After tapering of corticosteroids, a second relapse occurred.