Objective: Radiology plays a crucial role in diagnosis, work-up and staging of osteosarcoma. The main aim of the study is to review, analyze and characterize the imaging findings of a large series of histologically proven osteosarcomas focusing on the nonconventional subtypes. Methods: We retrospectively reviewed the imaging findings of 250 cases with histologically proven primary osteosarcoma. The study was conducted at King Hussein Medical Center and King Hussein Cancer Center, Amman-Jordan during the period 2003-2012. Approval by the ethical committee and institutional review board was taken from both institutions before starting the study. Patient demographic data was recorded. Images from plain radiographs (n =238), angiograms (n =28), bone isotope scans (n =56), computed tomography scans (n =99), computed tomography angiograms (n=27) and magnetic resonance imaging (n =189) were evaluated for the origin site, location, tumor size, matrix pattern, extrinsic and intrinsic characteristics and the soft tissue component of the tumor. The sample included 162 males (65%) and 88 females (35%), with an age range of 12-48 years (mean age of 23.5 years). Simple descriptive statistical methods (frequency, mean and percentage) were used to describe the study variables. Results: The most common histological diagnoses were conventional (n=193), telangiectatic (n=14), small cell (n=3), low grade central (n=3), high grade surface (n=2), parosteal (n=4), and periosteal (n=5) and non specific (n= 26). The most frequent origin site in the long bones is the metaphysis (80%) followed by diaphysis (9%), and less frequently the epiphysis (2%), 10% were found in the spine and flat bones. The commonest lesion location was distal femur (25%), proximal femur (18%), proximal humerus (17%), proximal tibia (15%), spine and flat bones (16%), other places (9%). The tumor size ranged from 2-21cm. The majority of cases (78%) demonstrated osteoid matrix abnormal mineralization, 32 of them showed obvious and marked mineralization, three cases with marked mineralization were noted in the spine, one of them gave an ivory vertebra appearance. A purely lytic pattern was seen in 48%. Soft-tissue components were seen in 58% of cases. Conclusion: This study provides a good relation between the radiological imaging and histological subtypes of osteosarcoma in a relatively large series of osteosarcoma and highlights our experience at King Hussein Medical and Cancer Centers.
