Abstract: Objective To analyze the CT and magnetic resonance imaging (MRI) manifestations of the pelvic osteosarcoma. Methods The CT and MRI manifestations of 15 cases with pelvic osteosarcoma from January, 2013 to December, 2015 proved by histology were retrospectively analyzed. Results There were 10 males and 5 females in them. The median age was 27.0 years. Ilium was involved in 11 cases. A mixed lytic/sclerotic pattern of bone destruction was found in 11 cases, and the sclerotic type in 2 cases, the osteolytic type in 2 cases. Radial periosteal reaction was found in 5 cases and immature bone formation in 8 cases. Soft tissue masses were seen in 13 cases. MRI showed enhancement in 15 cases and the CT showed no enhancement in 2 cases with sclerotic type. Conclusion The typical imaging manifestations of pelvic osteosarcomainclude mixed lytic/sclerotic appearance, radial periosteal reaction, soft tissue masses and immature bone formation.

Key words: osteosarcoma, pelvis, magnetic resonance imaging, tomography, X-ray