[Acute lymphoblastic leukemia accompanied by severe hypercalcemia; successful treatment with bisphosphonate]

A 62-year-old woman was admitted to the hospital because of bone pain. Laboratory data showed blasts in the peripheral blood, hypercalcemia (corrected calcium 15.1 mg/dl) and an increased level of parathyroid hormone related-protein (PTHrP). Bone marrow aspiration revealed increased lymphoblasts (96.5%), indicating acute lymphoblastic leukemia (ALL, L1). Subsequent radiological examination disclosed bone infiltration of ALL. Although the hypercalcemia was successfully treated with bisphosphonate, the PTHrP level remained high. After chemotherapy, the blasts in the peripheral blood disappeared and the PTHrP level normalized. We hypothesize that in the present case the production of PTHrP by lymphoblasts resulted in the hypercalcemic state. Although ALL is rarely accompanied by hypercalcemia, this case might help us to understand the relationship between ALL and hypercalcemia.