Objective To study the clinical, radiologic and pathologic characteristics and diagnostic methods of telangiectatic osteosarcoma for further improving the diagnostic ability.Methods The data of 10 patients with histologically proved telangiectatic osteosarcomas were retrospectively reviewed, and the clinical, radiologic and pathologic characteristics were further analysed in combination with the literature.All 10 patients were examined with X-ray and MRI, and 2 patients with CT.Results Telangiectatie osteosarcomas originated from inferior femur in 5 patients, femur neck in 1 patients, superior humerus in 2 patients and superior segment of tibia in 2 patients.The lesions showed osteolytic bone destruction on X-ray films (n = 10) and CT images ( n = 2), with mild bone expansion in 4 patients.The majority of the edge of the destroyed bone areas was unclear but without sclerotic rim.There were Codman's triangle and soft tissue mass in each patient but no obvious neoplastic bone forming.On MRI, all the lesions were mostly or completely constituted by the multiple cysts with periostnal reaction, and several scatteredly smaller liquid-liquid levels were found within cystic cavity in 7 patients.In all 10 cases, there were pathologic hemocoele similar to aneurysmal bone cysts (ABC), but malignant tumor cells and some neoplastic bones were found in cystic walls or septations.Only a small number of neoplastic bone tissue were seen by microscopy in 6 patients.Conclusions The radio-pathologic characteristics of telangiectatic osteosarcoma include the similar imaging findings of ABC, the common growth patterns of malignant tumors,and the pathologic hemocoele, malignant tumor cells within cystic wails or septations.The comprehensive analysis of clinical, radiologic and pathological data may help clinicans to make a correct diagnosis for telangiectatic nsteosareoma.