Soft-tissue uptake of technetium-99m MDP in multiple myeloma.

Abnormal accumulation of Tc-99m MDP in the lungs and stomach was observed in a patient with multiple myeloma and refractory hypercalcemia. There was no roentgenographic evidence of calcification. At postmortem examination, the presence of amyloid deposits was confirmed in both organs, while the corresponding metastatic calcification was demonstrated only in the gastric mucosa. It seems likely that, in our case, soft-tissue localization of bone-seeking agent was attributable to the presence of amyloid deposits rather than metastatic calcification. No cases showing the combined occurrence of amyloid deposition and metastatic calcification in soft-tissues have previously been demonstrated to concentrate bone-seeking agent.