Sunitinib-related high-grade proteinuria and allograft dysfunction in a kidney recipient: a rare case report.

backgroundSunitinib-induced high-grade proteinuria and irreversible renal allograft dysfunction are rare conditions. Here, we present a patient who had received renal allograft and later developed metastatic clear cell renal cell carcinoma(cc-mRCC), for which he was prescribed sunitinib. High-grade proteinuria, hypoalbuminemia, peripheral edema and renal allograft dysfunction (manifesting as an increase in the serum creatinine concentration) occurred 5 months after sunitinib prescription. CASE PRESENTATION: The patient was a 58-year-old male who had end-stage renal disease with regular hemodialysis through arteriovenous fistula for 17 years since 1998 and received a renal allograft from a deceased kidney donor in 2015. Unfortunately, in 2019, the patient developed cc-mRCC originating from the left native kidney. We suggested a needle biopsy on left native kidney or radical left nephrectomy, but the patient refused. Sunitinib was prescribed. Follow-up urine analysis showed proteinuria (500 mg/dL) 2 weeks after sunitinib prescription. He was hospitalized 5 months later because of body weight gain, decreased urine output, pitting edema of both lower extremities, and shortness of breath. The image studies showed progression in his cc-mRCC. His serum creatinine level and spot urine protein at admission increased to 4.26 mg/dL and 300 mg/dL, respectively. He agreed on a biopsy for the renal allograft and the pathology studies showed focal segmental glomerulosclerosis, acute interstitial nephritis, and acute tubular injury. Based on the time sequence of clinical presentations with the laboratory and pathological findings, sunitinib-induced renal allograft dysfunction secondary to high-grade proteinuria was most likely. Despite of discontinuation of sunitinib and increased dose of everolimus, renal impairment progressed. Thus, he had to receive hemodialysis starting 2 week after hospitalization. Unfortunately, the patient died of advanced metastasis despite of aggressive medical treatments 3 weeks after admission.

conclusionThis case report is a reminder that renal allograft dysfunction can happen secondary to proteinuria after taking sunitinib. Hence, clinicians must regularly check renal function and urine protein for renal allograft recipients. Monitoring and modifying drug prescription, especially sunitinib, is necessary if persistent proteinuria accompanied by deteriorating serum creatinine level occurs. Renal biopsy may be considered if more evidence is required to make a differential diagnosis.