Atezolizumab-induced Encephalitis in a Patient with Hepatocellular Carcinoma: A Case Report and Literature Review

We herein report a case of encephalitis in a 42-year-old woman with hepatocellular carcinoma following atezolizumab plus bevacizumab therapy. After two weeks of treatment, she was admitted for a high fever, impaired consciousness, and convulsive seizure refractory to diazepam. Magnetic resonance imaging revealed a hyperintense splenial lesion. A cerebrospinal fluid test excluded malignancy and infection. These findings were highly suggestive of a diagnosis of encephalitis due to atezolizumab, an immune-related adverse event. Steroid pulse therapy improved the fever and seizure. However, her incomplete right-sided paralysis and aphasia persisted. This is the first case report of encephalitis caused by atezolizumab plus bevacizumab therapy for hepatocellular carcinoma.