Development of complex renal cysts: A complication associated with Crizotinib therapy.

Crizotinib is a tyrosine kinase inhibitor that has been found to be effective in the treatment of anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer. This targeted cancer therapy agent has been shown to have superior efficacy over standard chemotherapy in this small subset of lung cancer patients. An adverse effect of this drug therapy is the development of complex renal cysts. Here, we present a case of a 68-year-old patient with non-small cell lung cancer on Crizotinib therapy who developed complex bilateral renal cysts. It is important to recognize this drug-related complication in order to avoid mistaking it for disease progression, primary renal malignancy, or renal infection.