Accumulation of Tx-99m phosphonate complexes in metastatic lesions from colon and lung carcinomas.

Cases are presented in which Tc-99m methylene diphosphonate accumulated in a lung metastasis from well differentiated adenocarcinoma of the colon, and in a hepatic metastasis from oat cell carcinoma of the lung. To our knowledge, this is the first report of Tc-99m phosphonate complexes concentrated in a pulmonary metastasis of colonic caecinoma or in a hepatic metastasis of oat cell lung carcinoma. The exact mechanism for this non-osseous uptake of bone scanning agents is still unknown.