Polycystic Liver Disease in a Patient With Metastatic Renal Cell Carcinoma: A Case Report.

We report a case of rapid evolution of polycystic liver disease in a 76-year-old patient with metastatic renal cell carcinoma who underwent treatment with numerous antineoplastic agents. The aim was to identify a causative etiology for these hepatic cysts of unclear origin. The cystic lesions of the patient were ultimately innumerable and developed rapidly, more than tripling the total liver volume from complete absence over the course of 24 months. The hepatic lesions continued to grow despite an otherwise moderate tumor response. Prior to patient death, the patient remained relatively asymptomatic from the cyst burden and was without signs of grossly metastatic disease. This rapid development of polycystic liver disease most likely represents a previously unseen medication side-effect of cabozantinib or pazopanib. It is important to identify adverse effects of novel antineoplastic agents in this time of oncological medical discovery.