Neurologic toxicity associated with interferon α therapy for renal cell carcinoma

A 67-year-old man received interferon alpha (IFN alpha) therapy for lung metastases of renal cell carcinoma (RCC). Multiple pulmonary metastases disappeared completely. However, neurological toxicity was detected by magnetic resonance imaging (MRI) as abnormal brain lesions. After discontinuation of IFN alpha therapy, his neurological symptoms and abnormal lesions on MRI disappeared completely. Complete remission of RCC has continued, and results of neurological study have remained normal for 5 years after discontinuation of IFN alpha therapy.