Hypercalcemia with nephrocalcinosis and impaired renal function due to increased Parathyroid hormone secretion at onset of childhood acute lymphoblastic leukemia.

The present case report contributes new aspects to the etiology and the appearance of hypercalcemia at the onset of childhood acute lymphoblastic leukemia [ALL]. Malignancy associated hypercalcemia is often associated with an increase of Parathyroid hormone-related protein [PTHrP]. In our case PTHrP was normal but high levels of Parathormon [PTH] were measured. This increase of PTH was not due to hyperparathyroidism nor was it due to osteolytic lesions or metabolic disease interfering with bone density. The most likely explanation for high PTH levels in our case was that PTH was secreted by leukemic blasts and thus responsible for hypercalcemia. Uncommonly, hypercalcemia was clinically associated with moderate renal impairment and marked nephrocalcinosis.