The scintigraphic abnormalities with radionuclide bone scanning observed in a patient with metastatic breast carcinoma associated with hypercalcaemia are described. Abnormal uptake of 99mTc-pyrophosphate was noted in the lungs, stomach, myocardium, kidneys, and thyroid, indicating metastatic visceral calcification. A scan performed 72 h later when she was normocalcaemic showed marked reduction in the accumulation in the myocardium and thyroid. In a further scan, 18 months later, no extraosseous uptake was present. A review of 26 reported cases of visceral metastatic calcification with scintigraphic abnormalities indicates that the changes in this patient were more widespread and that in only two of the previous cases similar total resolution had been observed. The reasons for the discrepancy between the incidence of visceral calcification on autopsy and on scintigraphic examination are discussed in relation to the aetiological factors. It is concluded that bone scanning offers a useful method for identifying visceral calcification, except when associated with uncomplicated renal failure, and is valuable in detecting this abnormality in patients with hypercalcaemia and in the assessment of response to therapy.