Right ventricular mass in a 10-year-old girl with osteosarcoma: an unusual case of asymptomatic cardiac metastasis

During routine surveillance imaging of a 10-year-old girl with osteosarcoma, a right ventricular filling defect was identified on contrast-enhanced chest computed tomography (CT).Sixteen months earlier, she was diagnosed with osteosarcoma of left distal femur, with lung metastasis.Response to chemotherapy was poor.After limb salvage surgery, chemotherapy was changed, followed by bilateral wedge resection of lungs.However, she developed another lung metastasis one month later.Despite switching chemotherapy, she experienced left buttock pain.Magnetic resonance imaging (MRI) revealed lumbar spine metastasis.Radiation therapy and extradural tumor excision provided temporary pain relief.Chemotherapy was changed, however, her tumor rapidly progressed to involve thoracic spine, and left femur.She showed no respiratory or cardiac symptoms, and vital signs were normal.Physical examination revealed no signs of heart murmur, lower limb swelling, or hepatome galy.Contrast-enhanced chest CT revealed multiple no dules, along with an unexpected filling defect in right ventricle (Fig. 1).The pulmonary artery and inferior vena cava were patent.