Infected complex renal cysts during crizotinib therapy in a patient with non–small cell lung cancer positive for ALK rearrangement

Summary Crizotinib is the first clinically available tyrosine kinase inhibitor that targets anaplastic lymphoma kinase (ALK) and is associated with the development of complex renal cysts. We now describe a 39-year-old woman who developed infected complex renal cysts during crizotinib treatment. After 10 months of such treatment, she presented with a high fever and low back pain. Computed tomography findings were consistent with complex renal cysts and perilesional inflammation. Interventions including cyst drainage and antibiotic administration contributed to diagnosis and management of the infected cysts.