extreme anger in my four year old son

[mrsmegah6425]

I have been dealing with my toddlers extreme aggression since he was two years old. He only has problems in a school or daycare setting. While at school or daycare he had been know to throw chairs spit in teachers faces, pretend to stab kids with scissors, rip things off walls, punch teachers in their stomachs, kicks and hits other children..im getting worried about him and i have no idea where to go next hes getting out of control. 

[Bokonon]

Has he been seen by a developmental pediatrician?  What does his doctor say?