Progressive soft tissue uptake of Tc-99m MDP reflecting metastatic microcalcification.

A 49-year-old woman had longstanding renal impairment. Markedly increased uptake of Tc-99m MDP in the heart, lungs, and kidneys was an incidental finding on bone scintigraphy performed to exclude metastatic bone disease. These findings persisted on repeat bone imaging 1 year later. In addition, gastric and skeletal muscle uptake was subsequently seen. Soft tissue microcalcification was confirmed by computed tomography and renal biopsy. A consideration of the differential diagnosis is presented.