Hypercalcemia As the Sole Initial Presentation of Precursor B-cell Acute Lymphoblastic Leukemia

A 24-year-old female presented with nausea, vomiting and abdominal pain. Physical examination was unremarkable. The patient's laboratory studies showed calcium of 17.2 mg/d, white cell count: 9,000/mcL with a normal peripheral blood smear. The patient had low PTH and PTHrp. She was hydrated, given calcitonin of four units/kg every 12 hours subcutaneously for 24 hours and zoledronate IV 4mg given once, with which calcium levels normalized and symptoms resolved. The patient returned one week later, with bone pain and bruises. Platelet count: 51,000/mcL, WBC count: 9,000/mcL, with lymphocytosis. A peripheral smear showed lymphoblasts. Flow cytometry confirmed precursor B-cell acute lymphoblastic leukemia (ALL) with 43% blasts. Hypercalcemic patients may have blasts at presentation, but can be "aleukemic." Unexplained hypercalcemia with bone pain should lead to the suspicion of ALL, and a bone marrow exam should be performed even without peripheral blastosis to diagnose and treat ALL immediately.