Lenvatinib-Associated Posterior Reversible Encephalopathy Syndrome in a Patient With Metastatic Clear Cell Renal Cell Carcinoma: A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a rare but serious neurologic complication associated with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors, including lenvatinib. We report a case of PRES in a 63-year-old woman with metastatic clear cell renal cell carcinoma treated with pembrolizumab and lenvatinib for isolated pancreatic metastases. Two days after lenvatinib initiation, she developed headaches, confusion, visual hallucinations, and a generalized tonic-clonic seizure in the setting of severe hypertension. Brain magnetic resonance imaging demonstrated bilateral parieto-occipital vasogenic edema consistent with PRES. Lenvatinib was discontinued, and she was treated with antihypertensive and antiepileptic therapy, with complete clinical recovery within two weeks with radiographic resolution on follow-up imaging. Pembrolizumab was maintained as monotherapy without PRES recurrence. This case highlights the importance of prompt recognition, drug discontinuation, blood pressure control, and supportive management in patients who develop neurologic symptoms shortly after starting VEGFR tyrosine kinase inhibitors.