Case Report: Radionuclide Detection of Multiple Soft Tissue Metastases of Osteosarcoma Masquerading as Bone Metastasis

Objective: The aim of this work was to report an unusual case of multiple soft tissue metastases of osteosarcoma detected using bone scan and confirmed by CT scan. Clinical Presentation and Intervention: A 15-year-old patient with a history of osteogenic sarcoma presented with fatigue and loss of appetite in addition to a painless swelling of the distal left lower extremity. Bone scan and chest CT scan were performed for restaging purposes. The bone scan revealed multiple bone metastases and suspected tumor recurrence in the left lower extremity in addition to multiple extraosseous hot spots. The latter findings were assessed as ossified soft tissue metastases after considering the performed CT scan. Conclusion: This case showed the double role of bone scan in osteosarcoma in simultaneously assessing the bone status and tumor spread in soft tissue. The benefit of a comparison of bone scan findings with other modalities was also demonstrated.