Anderson Cooper Explains Absence: Emergency Appendectomy

Anderson Cooper explained his on-air absence on Monday with a tweet that he had surgery to remove his appendix Sunday night.

I'll be back on air tomorrow. Had an appendicitis and had to have sudden surgery last night

— Anderson Cooper (@andersoncooper) December 2, 2014

John Berman sat in for Cooper as host of "Anderson Cooper 360" on Monday night but made no mention during the show's opening or closing of why Cooper was absent.