[Two cases of incidentally detected renal arteriovenous fistula over ten years after renal biopsy].

CASE 1: The case was a 66-year-old Japanese woman. A renal biopsy had been carried out at 53 years of age, and she was diagnosed as IgA nephropathy. Her renal function had been stable at around 0.7 mg/dL of serum creatinine. At 66 years of age, macrohematuria was found and she was admitted to hospital. Enhanced abdominal computed tomography showed left renal arteriovenous fistula (AVF) (21 mm x 10 mm), and hydronephrosis. Her renal AVF was successfully treated with coil embolization, and hydronephrosis was improved with stable renal function. Her AVF was cirsoid type, which is usually congenital, although it was not recognized before the renal biopsy. CASE 2: A 48-year-old Japanese woman was referred to a nephrologist for proteinuria and an elevated serum creatinine level. She had undergone two renal biopsies when she was 14 and 18 years of age and her condition had been diagnosed as chronic glomerulonephritis. However, she had not received any special treatment. Upon abdominal ultrasonography, a right renal AVF (18 mm x 23 mm) was detected. Her aneurysmal type AVF was successfully treated with coil embolization. In these 2 cases, renal biopsy might be a cause of renal AVF. Regular screening test using ultrasonography is recommended to avoid missing remote complications of renal biopsy.