Extraosseous uptake of 99mtechnetium methylene diphosphonate: neuroblastoma or radiation therapy.

A child with a ganglioneuroblastoma and tumor uptake of 99mtechnetium methylene diphosphonate (99mTc-MDP) is presented. After surgical removal of an encapsulated tumor and radiation therapy, an interval bone scan demonstrated the same presurgical abnormality. Awareness of abnormal uptake of 99mTc-MDP in irradiated renal tissue prevents interpreting radiation nephritis as recurrent tumor.