Lung uptake of technetium 99m methylene diphosphonate due to focal metastatic calcification

Extraskeletal uptake of bone-seeking radiopharmaceuticals occurs at sites of a variety of underlying disease processes (Heck, 1980). Uptake in areas of pulmonary metastatic calcification in patients with hypercalcaemia has been recorded (Grames et al, 1974; Richards, 1974; Rosenthal et al, 1977). Recently it has been suggested that the combination of hypercalcaemia and local tissue ischaemia may account for high local uptake of 99Tcm methylene diphosphonate in lung (Wraight, 1983). The following case was clinically similar to that reported by Wraight, but provides pathological evidence that such an association was not the cause of tracer uptake in the lung. The tracer uptake occurred in an unusually well localised form of metastatic calcification in the lung and was separate from an area of infarction.