From the little observation I've made and talking to one or two in healthcare disciplines, medics at the top of their profession seem to be treated like gods with no questioning of their actions allowed or tolerated. Juniors seem to operate in fear of their master who holds the key to their career progression and management seem loath to tackle them for whatever reason.
I am of course thinking of the most recent case where mis-diagnosis has gone unchecked for years and the surgeon has just been handed a 15 year jail sentence It seems like there are few checks and balances to quickly identify rogue practioners or people dare not speak up.
Old Deuteronomy is right - cases like this one are very rare. That doesn't make them any the less horrendous, and quite obviously the man involved should never have been allowed to do what he did without any apparent attempt being made by colleagues to stop him.
Extreme cases like this are rare, but I wonder how many people are misdiagnosed and are afraid to speak out about it.
I know my wife was misdiagnosed by her doctor before we were married and when I found out what she was being treated for I managed to persuade her to see a different doctor in a different practice and he correctly (I assume) gave her different treatment which solved the problem permanently within a couple of weeks.