XANTHINE STONE AND XANTHINURIA ASSOCIATED WITH RETROCAVAL URETER: REPORT OF A CASE AND A REVIEW OF THE LITERATURE

A 5-year-old boy was first seen on April 10, 1973, with a complaint of gross hematuria and right flank pain. An x-ray examination revealed a retrocaval ureter with a non-opaque stone in the upper portion of the ureter. The stone was interpreted as a xanthine stone, because serum and urinary uric acid levels were very low and serum and urinary oxypurine levels were very high (Table 1).On October 1, 1974, he was operated upon. A chocolate-colored, smooth, oval and easily broken stone was removed from the right ureter which encircled the vena cava. The ureter was completely freed and restored to normal position with an end-to-end anastomosis. The stone consisting of 93.5% of xanthine measured 2 by 1.3 by 1cm and weighed 2.3g showing many concentric rings on section. Post operative course was uneventful. He was dicharged on October 22, 1974.Etiology of xanthine stone formation was briefly discussed.