From Wikipedia, the free encyclopedia.
A teratoma is a type of tumour that derives from pluripotent germ cells. Teratomas usually start from cells in the testes in men, the ovaries in women and in the sacrum in children. Teratomas involve cells from all three embryonic cell layers: ectoderm, mesoderm and endoderm. They can be benign or malignant.
Teratomas often contain well-differentiated cells which can result in tissues growing in a teratoma which are quite different to the surrounding tissue - ovarian teratomas have been known to grow hair and teeth. Testicular teratomas are generally less well-differentiated, and have a worse prognosis (chances of recovery are not as high).
