Accelerated phase of chronic myeloid leukemia presenting with hypercalcemia and a mediastinal mass

A patient with chronic myeloid leukemia developed hypercalcemia as a presenting sign of the accelerated phase of the disease. Ultrasound of the neck showed a large hypodense mass connected to the thyroid gland, which was thought to be a parathyroid tumor and the cause of the hypercalcemia. Histology of the surgically removed mass revealed a chloroma. The patient's course was complicated by respiratory failure and metastatic calcinosis of the lung, an unusual finding in hypercalcemia of short duration.