Sunitinib-Induced Acute Interstitial Nephritis ina Thrombocytopenic Renal Cell Cancer Patient

Sunitinib, a multitargeted tyrosine kinase inhibitor (TKI), is currently the standard of care for patients with metastatic renal cellcarcinoma. Renal adverse events associated with sunitinib include proteinuria, renal insu4ciency secondary to focal segmentalglomerulosclerosis (FSGS), and thrombotic microangiopathy. We describe the second reported instance of biopsy-provensunitinib-induced acute interstitial nephritis (AIN), in a challenging case complicated by thrombocytopenia. +e case illustratesthe importance of early diagnosis and intervention in ensuring long-term recovery from renal complications. Four other cases ofAIN reported along with inhibition of the vascular endothelial growth factor (VEGF) by either TKI (sunitinib and sorafenib) orantibodies (bevacizumab) suggest a possible class effect. Given our experience, we recommend monitoring renal function withVEGF inhibition, and in the case of renal failure in the setting of an unclear diagnosis, we recommend prompt biopsy.