That is an interesting question because if someone could actually spontaneously combust then how would they keep from burning everything around them. Unless someone put out the fire it would seem impossible.
My mom had a disorder when I was young, and burned from the inside out. (She lived,btw). Her doctor said she burned from the inside and it caused her skin to blister. Thick skin fell off in chunks over a month's time, but it was thick heavy sheets of skin, not flimsy like a sun burn peel. It's never happened since, she's ok, but I've always wondered if it was something short of combustion.
Rhonda that sounds horrendous! I'm glad she is fine now and recovered from whatever it was. As for the topic of this thread, I don't have any definite opinion but this article is interesting and provides some scientific explanation for what happens.
The human body is basically very flammable. The spark can also come from electrical impulses that shoot up and down your nervous system, that's the theory, in practice we are ignoring the fact that we are 70% water and no fire burns without affecting nothing else, it just physics, heat is energy and energy get's absorbed by everything.
The article that Chintai shared explained that fats in the body could be the material that help keep the heat inside the body and not away from it. Still I think fats can catch flame easily so why is it that the fats didn't burn quickly?
I wouldn't be surprised if human combustion was a real thing because there are STILL things that doctors and scientists don't know about the human body. Have you guys heard about the fact that we only use a very small portion of our brain? There are large spaces of the brain that scientists don't know the importances of yet- who's to say that there isn't some little sleeping portion of the brain that could cause the whole body to ignite?