骨外骨肉瘤(extraskeletal osteosarcoma,EOS)是一种发生在骨骼以外的骨肉瘤,与发生在骨骼内的骨肉瘤相比,其发病率低得多。该病多发生于中老年人,男女之比约2∶1,较常见的部位是深部软组织如大腿肌肉内、腹腔、纵隔等。现报告1例发生在大网 Extraskeletal osteosarcoma (EOS), an osteosarcoma that occurs outside the skeleton, is much less common than osteosarcoma that occurs in the bones. The disease occurred in the elderly, male to female ratio of about 2: 1, the more common sites are deep soft tissue such as thigh muscle, abdominal cavity, mediastinum and so on. One case is now reported in the big network