The line is not very distinct. In fact, the "Word of Faith" movement is cultic as is almost everyone on the Trinity Broadcasting Network (Benny Hinn, Paul Crouch, etc).
Pick up Hank Hanegraaf's (the Bible Answer Man) book "Christianity in Crisis". He goes into detail how Christianity has been hijacked by cultic leaders.
Cultists have always tried to hijack Christianity. They have not succeeded, and never will. God is still in control.
As a second thought: the most successful hijacking of Christianity by a cult goes by the name "Islam".