Case Report of Renal Calculi in a Child Receiving Imatinib for Acute Lymphoblastic Leukemia.

RATIONALE: Imatinib is used in the treatment of Philadelphia chromosome positive (Ph+) leukemias and has been reported to have a direct effect on bone physiology.

PRESENTATION: To report on a child with Ph+ acute lymphoblastic leukemia who presented with bilateral flank pain and gross hematuria.

DIAGNOSIS: She was diagnosed with obstructive kidney stones 101 days after commencing daily oral imatinib. Stone analysis revealed the presence of calcium phosphate.

INTERVENTIONS AND OUTCOME: The patient passed the stones spontaneously with medical therapy that included the use of thiazide, allopurinol, and potassium citrate, but she required temporary insertion of a double-J stent to relieve an obstruction.

NOVEL FINDINGS: Imatinib inhibits receptor tyrosine kinases and stimulates the flux of calcium from the extracellular fluid into bone, resulting in hypocalcemia with a compensatory rise in parathyroid hormone that may result in phosphaturia and the formation of calcium phosphate stones. Given that kidney stones are rare events in children, we believe that monitoring for kidney stone formation needs to be performed in children receiving imatinib.