Delayed accumulation (flip flop) of Tc-99m DTPA in a leiomyosarcoma.

An 85-year-old woman with leiomyosarcoma occupying the abdominopelvic area had a renal dynamic study with Tc-99m DTPA. The tumor area initially showed almost no content of the radiopharmaceutical. At 24 hours, there was retention of activity in the leiomyosarcoma as compared with surrounding tissues (flip flop). It was noted that, based on literature reports, tumors of mesodermal origin (leiomyoma, spindle cell sarcoma, neurofibroma) may have the ability to concentrate Tc-99m DTPA.