Albeit rare, renal vein abnormalities on autopsy and in cases of abdominal surgery complications have been reported and should be kept in mind when performing invasive procedures, such as renal biopsy. We detected a rare renal vein abnormality on colour Doppler ultrasound before renal biopsy, thereby, avoiding a haemorrhagic complication. A 10-year-old boy presented to our department for the first time because of incidental findings of haematuria and proteinuria. We suspected chronic glomerulonephritis and scheduled an ultrasound-guided percutaneous renal biopsy. A simple screening ultrasound at the initial visit revealed no renal or vascular abnormalities. The day before the renal biopsy, we confirmed the biopsy site by performing a colour Doppler ultrasound, which showed abnormal blood flow from the lower pole of the left kidney, which was the planned puncture site; therefore, we changed the biopsy site to the right and completed the examination. Subsequent computed tomography angiography depicted two renal veins; one was the usual left renal vein draining from the kidney hilum, and the second was an accessory vein draining from the inferior pole of the left kidney and entering the inferior vena cava through the dorsal side of the aorta. Although rare, abnormalities in the renal vessels on the inferior pole of the kidney, which is the usual site of renal biopsy, are essential to rule out preoperatively by colour Doppler ultrasound, because these can cause significant bleeding during renal biopsy if not recognized.
Keywords: accessory vein; left renal vein; polar vein; renal biopsy; renal vein anomaly.
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