Hypercalcemia in acute lymphoblastic leukemia: an overview.

Hypercalcemia usually results in nonspecific constitutional symptoms, although it can also manifest as a life threatening metabolic emergency. It is an uncommon albeit well recognized biochemical feature of childhood malignancies including acute leukemia. The pathogenesis of hypercalcemia and its implications in terms of long-term outcome are not yet fully understood. Most of the children presenting with acute lymphoblastic leukemia and hypercalcemia tend to be in older age groups and have an absence of blasts in the peripheral blood film. The chromosomal translocation 17;19 seems to be more frequent in children who present with hypercalcemia but the presence of hypercalcemia by itself does not seem to be closely linked to prognosis. Some of the less common immunophenotypes in the form of CD19 negativity and CD10 positivity have also been observed in hypercalcemic patients. In this study, we shall illustrate this clinical problem using the details of 2 patients with hematologic malignancy who were found to be hypercalcemic at presentation. We shall also review the literature with particular emphasis on the pathogenesis of hypercalcemia, its associations, and relationship to outcome.