Radionuclide detection of multiple soft tissue metastases of osteosarcoma masquerading as bone metastasis

Metastasis of femoral osteosarcoma to the abdominal wall detected on 99m Tc-MDP skeletal scintigraphy

Osteosarcoma is the most frequent primary malignancy of bone, and usually metastasizes to the lung and bones, while other sites are rare. In most reported cases, soft tissue metastasis of osteosarcoma is unusual, and only develops in the advanced stages of the disease, especially following multiple recurrences. We present a patient with recently diagnosed osteosarcoma of the right femur, showing abdominal wall metastasis diagnosed by technetium-99m-methylene diphosphonate (99m Tc-MDP) whole body bone scintigraphy and confirmed histologically. The present case highlights the importance of whole body imaging of patients with osteosarcoma for detecting unusual sites of metastasis, especially in soft tissue organs.