Guillain-Barré syndrome in a patient with renal cell carcinoma following the first course of pazopanib therapy.

Pazopanib, one of the antiangiogenic drugs, has recently become a first-line treatment for metastatic renal cell carcinoma. The most common adverse effects of pazopanib include diarrhea, fatigue, and nausea, but neuropathic complication has not been documented. Here, we report the first case of a patient with metastatic renal cell carcinoma who developed acute neuropathy mimicking Guillain-Barré syndrome following the first course of pazopanib therapy. A 75-year-old man with a metastatic renal cell carcinoma was admitted for rapidly progressive weakness and numbness in the extremities after the first course of pazopanib therapy. Neurological examination revealed symmetrical distal limb weakness, sensory disturbance, and areflexia. Based on the clinical pictures, conduction slowing on the nerve conduction studies of the extremities and albuminocytologic dissociation on the cerebrospinal fluid examination, a diagnosis of Guillain-Barré syndrome was made. After discontinuation of pazopanib and a subsequent high-dose intravenous immunoglobulin therapy, symptoms rapidly resolved and the patient became ambulatory with a cane. Serological and neuroradiological examinations failed to reveal any possible causes for the neuropathy other than pazopanib. While the benefits of pazopanib for metastatic renal cell carcinoma far outweigh this neurotoxic effect, physicians prescribing this drug should be aware of this rare complication of neuropathy.