Retrocaval ureter and the diagnostic utility of dynamic scintigraphy: A case report

Retrocaval ureter is a rare congenital anomaly characterized by the persistence of posterior cardinal veins in front of the ureter due to their failure to regress in early embryonic development. Its main symptoms are discomfort, right flank pain, hematuria, recurrent infections, fever, and stone formation. A seven-yearold male patient presented with hematuria. Urinary ultrasound revealed Grade 2 hydronephrosis in the right kidney and dilation in the right proximal ureter. Considering the possibility of ureteropelvic junction obstruction, dynamic renal scintigraphy was performed which showed radiopharmaceutical accumulated in the mid-segment of the right ureter, likely due to compression that did not pass distally. To confirm the diagnosis, retrograde pyelography was performed perioperatively, and it was consistent with the retrocaval ureter. Laparotomy showed that the ureter ran behind the inferior vena cava from its mid-segment. A ureteroureterostomy was performed, the ureter was positioned anterior to the inferior vena cava, and a ureteral stent was inserted. In conclusion, renal scintigraphy traditionally provides information about the degree of obstruction and renal function. However, as in the presented case, the examination of dynamic renal scintigraphy images showing the accumulation of radiopharmaceutical substance in the mid-segment of the ureter and the absence of the distal ureter may indicate a retrocaval ureter. It is, therefore, of utmost importance for clinicians to review the images obtained from dynamic scintigraphy in cases of obstructive uropathy and recognize the possibility of retrocaval ureter.