Synchronous multifocal osteosarcoma with lymphatic spread in the lung: an autopsy case report.

Synchronous multifocal/multicentric osteosarcoma (MOS) is a rare variant of osteosarcoma. We report here an autopsy case of a 15-year-old boy with MOS. Radiological examinations showed multiple sclerotic lesions in the left distal femur and in the ipsilateral proximal tibia without pulmonary metastasis at the first examination. Histological examination showed osteoblastic-type osteosarcoma. Despite high-dose chemotherapy the patient died of multiple bone and lung involvements 6 months after the initial diagnosis. Autopsy examination revealed prominent invasion of the tumor cells into lymphatic vessels and pleural dissemination without the formation of bulky, nodular metastasis in the lungs. Metastases in pulmonary hilar lymph nodes were noted without metastasis in other organs. Immunohistochemistry revealed that p53 protein was positive in most of the tumor cells. In summary, the present case was characterized by multiple bone involvement and prominent lymphatic spread of sarcoma cells in the lungs.