[A case of crizotinib-associated renal cysts].

Crizotinib-associated renal cysts (CARC) are the development of new renal cysts or pre-existing renal cysts after the treatment with crizotinib. Most CARC disappear after crizotinib is stopped. A few CARC showed aggressive behavior that could go beyond the invasion of the renal cortex into nearby structures, including perirenal space, psoas major muscle, intestine, and abdominal wall. A case of EML4-ALK fusion mutation in invasive lung adenocarcinoma has been reported. Multiple cystic changes occurred repeatedly in both kidneys, right rectus muscle, and psoas major muscle after treatment with crizotinib, and spontaneous absorption and resolution after discontinuation of the drug.