[Osteosarcoma of the pelvisTwo case reports and review of the literature].

Primary malignant neoplasms of the bone are rare. One of the most common bone tumors is osteosarcoma, most often localized in the metaphysis of adolescent long bones. The sacrum is concerned in only about 1%. Primary bone sarcomas of the pelvis are usually recognized after they have grown to a considerable size. Osteosarcoma patients from Germany, Austria, and Switzerland are treated by neoadjuvant chemotherapy combined with complete surgical excision according to the Cooperative Osteosarcoma Study Group (COSS). Based on a review of the literature, diagnosis, treatment, and complications of two cases of sacrum osteosarcoma are introduced.