Life-threatening Hypercalcemia as the First Manifestation of Acute Lymphoblastic Leukemia.

Hypercalcemia of malignancy, usually reported in adults in advanced stages, is rare in children. A 4-year-old boy presented with intermittent episodes of severe hypercalcemia, which improved with intravenous hydration therapy, furosemide and bisphosphonates as the initial manifestation of occult acute lymphoblastic leukemia. Pediatricians should rule out hematological malignancy in patients with severe hypercalcemia.