Renal dysfunction and hyperuricemia at presentation and relapse of acute lymphoblastic leukemia.

Hyperuricemia is an unusual presenting feature of acute lymphoblastic leukemia (ALL) and is generally associated with a large leukemic cell burden. We describe three children with T-cell ALL who presented with acute renal failure and very high serum uric acid concentrations, despite a relatively small leukemic cell burden. Two of the three patients had normal complete blood counts without circulating blasts or other physical evidence of leukemia. An isolated renal relapse in one case was associated with hyperuricemia, increased renal excretion of uric acid, and renal dysfunction. An unusually high rate of purine catabolism of the lymphoblasts may cause hyperuricemia in these cases. Unexplained hyperuricemia should prompt a search for occult malignancy.