Two-dimensional ultrasonic features were classified by echo partern:hypoechoic in 21 cases(48.8%),mixed echoic in 13 cases(30.2%),hyperechoic in 8 cases(18.6%),cystic in 1 case(2.3%).

• 二维声像图表现:低回声型21例(48.；8%25)；混合回声型13例(30