Unusual Soft Tissue Uptake of 99mTc-MDP in Radiation-Induced Sarcoma: Diagnostic Conundrum

99mTc-MDP is a bone imaging agent used for skeletal staging but can also be localized in extra osseous calcifying lesions. We report a case of an 84-year-old woman with breast carcinoma underwent surgery followed by radiotherapy 10-years back, now presented with right axillary mass referred for 99mTc-MDP to exclude bone metastasis. 99mTc-MDP shows intense tracer uptake is seen in the right thoracic region corresponding to the site of calcified soft tissue mass in right lateral chest wall. Subsequent ultrasonography showed ill-defined lesion contains coarse calcifications. Biopsy showed radiation induce sarcoma. Extra osseous 99mTc-MDP uptake may provide important diagnostic information that might alter patient management.