Osteosarcoma pulmonary metastasis mimicking abnormal skeletal uptake in bone scan: utility of SPECT/CT

We present a case of a 15-year-old boy with osteoblastic osteosarcoma of the left distal femur. The patient was referred to bone scan for initial staging. On planar bone scan, there is increased uptake of 99mTc-MDP (99mTc-methylene diphosphonate) in the left distal femur. There are also multiple sites of abnormal tracer uptake projecting to the thoracic cage, initially assumed to be localized in the ribs. SPECT/CT correctly identified them as pulmonary metastases. This case illustrates the potential advantages and utility of SPECT/CT imaging of skeletal bone scan in order to decide on the optimal treatment.