99MTc-metyhlene diphosphonate concentration in soft tissue malignant fibrous histiocytoma

Four cases of non-calcifying soft tissue malignant fibrous histiocytoma are presented which showed concentration of 99mTc-methylene diphosphonate. Angiography was performed in one of the patients and it featured hypervascularity, tumor staining and early draining veins indicative of arteriovenous shunting. As with other extraskeletal non-calcifying entities which exhibit enhanced uptake of 99mTc-phosphate complex, the mechanism of concentration is largely conjectural. Malignant fibrous histiocytoma can be added to the expanding list of conditions which may portray in avidity for 99mTc-phosphate complex.