Metastasis of osteosarcoma to the trapezius muscle: a case report.

Metastasis of a primary osteosarcoma to the muscles is extremely rare. As there have been few reported cases, the necessity of surgical treatment for such metastatic lesions remains controversial. We present the case of a primary osteosarcoma with development of a solitary metastasis to the trapezius muscle during chemotherapy for pulmonary metastasis. The patient was a 51-year-old man diagnosed with osteosarcoma of the right tibia. After undergoing chemotherapy and femoral amputation, he developed pulmonary metastasis. Chemotherapy was reinitiated, however, after approximately 1 year a palpable tumor was identified in the patient's right shoulder. This tumor grew and was associated with pain in the right shoulder. It was surgically removed 3 years after the re-initiation of chemotherapy. The pathological diagnosis was osteosarcoma with metastasis to the trapezius muscle. Although the patient died of respiratory failure due to pulmonary metastasis 14 months after resection of the metastatic lesion in the trapezius muscle, no new extrapulmonary metastasis was observed after the resection.