It went to HR. I got interviewed. I assume he got interviewed. He was not fired. He never spoke that way to me again. I eventually reestablished trust with this man and we got on well. I suspect he got sensitivity training. I was not told what went down. It was all handled very discreetly.
Please do get HR involved. Please do not listen to the people here who are advising you to nuke the man from orbit, it's the only way. Doing that will only deepen the problem. Men and women need to learn to interact at work. Promoting fear and loathing will not further that larger goal.
You get his side. You do some training. If it continues to be a problem, sure, fire him. But please do not use final solution/terrorist tactics. This only hurts women in the long run. Men need to learn better manners. Cutting their nuts off for a faux pas doesn't teach them that. It promotes a hostile environment between the genders. It doesn't create a more civil environment.