The authors analyzed 18 cases of telangiectaticosteogenic sarcoma,which consisted of 11.1% of thetotal admissions of osteosarcoma during the sameperiod.There were 13 males and 5 females.61% ofthe cases were less than 20 years of age.The durationof illness was less than 6 months in 66% of the cases.72% of the lesions occurred around the knee.Acystic appearance and a pulsatile sign were the chief