Chondromyxoid Fibroma of the Rib on 99mTc-MDP SPECT/CT.

A 37-year-old woman with persistent right-sided back pain. 99mTc-MDP SPECT/CT demonstrated a solitary focus of intense radiotracer uptake corresponding to the rib lesion. The patient declined percutaneous biopsy. The rib was excised because malignancy was still a concern. Histopathologic examination confirmed chondromyxoid fibroma (CMF). CMF rarely involves the ribs but can show intense ⁹⁹ᵐTc-MDP uptake. A solitary MDP-avid bone lesion on SPECT/CT should therefore be interpreted cautiously, as uptake intensity alone cannot distinguish benign from malignant disease.