Hypercalcemia in children presenting with acute lymphoblastic leukemia.

Although hypercalcemia is a well-recognized complication in malignant disorders, neither the incidence and prognostic significance of hypercalcemia, nor the role of parathormone related peptide (PTHrP) in pediatric acute lymphoblastic leukemia (ALL) have been clarified. Of 83 newly diagnosed pediatric ALL patients with early pre-B cell phenotype treated at our hospital during the last 8 years, four patients were diagnosed as having hypercalcemia (> 14 mg/dl). In these 4 hypercalcemic ALL patients at onset, serum calcium levels ranged from 14.6 to 20.8 mg/dl (normal 7.4-9.0 mg/dl), and serum PTHrP levels were markedly elevated to 112-240 pmol/l (normal range: 17.6-61.2 pmol/l). Unlike patients with ordinary ALL in childhood, gastrointestinal symptoms (nausea, vomiting, abdominal pain) and skeletal symptoms (bone pain, gait disturbance) were the chief complaints. Because of these characteristic symptoms, bone marrow aspiration was carried out in two patients in an attempt to diagnose ALL before leukemic cells appeared in peripheral blood. Serum calcium levels were promptly normalized by induction chemotherapy. The four patients have been in complete remission from 35+ to 125+ months. Based on these results, the incidence of hypercalcemia in pediatric ALL patients with early pre-B cell phenotype at our institute is calculated to be about 4.8%. Gastrointestinal and skeletal problems are the characteristic initial symptoms, and hypercalcemia does not seem to be significant in the prognosis of these patients.