Pulmonary uptake of Tc-99m-Labeled methylene diphosphonate in a patient with a parathyroid adenoma

Intense diffuse uptake of Tc-99m-labeled methylene diphosphonate was seen in both lungs of a patient submitted to surgery for a primary parathyroid adenoma. Five scans performed over the 3 yr following the operation showed persistence of lung uptake despite restoration of normal blood calcium concentration. Mild chronic renal failure caused by the hypercalcemia also persisted postoperatively. The present case confirms that pulmonary uptake of bone tracer can occur asymptomatically when both hypercalcemia and renal failure are present. Lung uptake of a bone tracer probably reflects tissue deposition of hydroxyapatite rather than of amorphous structures. Correction of the hypercalcemia failed to resolve the abnormal scan pictures.