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

Doctor here

Only very specific, rare types of tumors grow hair and teeth and the like, theyre called “teratoma”

Basically, these types of tumors contain a special kind of stem cell called Germ Cells. Germ cells are also known as sperm cells in men, and egg cells in women. These germ cells start to grow human tissue like teeth cells, eyes, hair, like theyre developing a fetus.

Generally, these types of tumors are often found inside the reproductive system, in ovaries and testes