Massive metastatic pulmonary calcification in an infant with aleukemic monocytic leukemia

An 18-month-old infant with aleukemic monocytic leukemia and osteoclastic bone resorption demonstrated in the pelvis, vertebral bodies, and ribs developed severe refractory hypercalcemia. Bilateral interstitial pulmonary radiopacities developed rapidly, accompanied by hypoxemia and hypercapnea. Von Kossa staining of an open lung biopsy revealed extensive, finely granular metastatic septal calcifications not apparent on H&E-stained sections. Autopsy revealed the massive nature of the pulmonary calcinosis and the presence of additional calcifications in the atrial subendocardium, liver, kidneys, vessels, and skin. Metastatic pulmonary calcification has been infrequently described in infants, and premortem detection of such deposits has been rarely reported. The Von Kossa stain is useful in detecting minute pulmonary calcifications which may radiographically simulate infiltrates of infectious origin.