Xanthine lithiasis, nephrocalcinosis, and renal failure in a leukemia patient treated with allopurinol

An 11-year-old boy who presented in acute renal failure with significant increases of uric acid and phosphorus in his serum was discovered to have acute lymphoblastic leukemia. Five years later, he had a second and similar episode of acute renal failure, which was responsive to hemodialysis. After three months of daily therapy with allopurinol, a third and final episode of renal failure was unresponsive to peritoneal dialysis. Autopsy revealed an obstructive uropathy; focal nephrocalcinosis; and multiple, small, tan calculi in the calyces of both kidneys. Systemic cryptococcosis was also discovered. The stones, characterized by paper chromatography, electrophoresis, x-ray diffraction, and infrared spectroscopy, were 82% xanthine, 15% oxypurinol, and 3% hypoxanthine. We suggest that attention to the effects of accelerated tumor-cell lysis may protect renal function in patients with a large and drug-sensitive tumor cell load. Similarly, early detection of the fungal complications of leukemic therapy is an essential component of the treatment program.