How do tumors grow things like eyes, teeth, brain tissue and organs when the human body often can’t grow those by itself?

Question

There was a post about a woman who grew a “homonculus tumor”, with brain tissue, teeth, a spinal nerves and other organs. But how? Human bodies can’t grow those things after birth, AFAIK. For example, once your adult teeth are in, that’s it. So how are tumors able to do this? Are the cells in tumors different from those found normally in human body?

In: 1354

Answer 1

These kind of growths are called teratomas. The basic idea behind them is that at some point during your very early development, when you are still essentially just a tube of cells, some of these cells that would end up being programmed to do one sort of thing end up getting dislodged and moved to another part of that tube. So if you have a growth with teeth that is in your foot, that means that those cells were originally going to be jaw cells, already started started to differentiate into that, and then they ended up getting dislodged and moved.