Teratomas are tumors composed of multiple tissues foreign to the site of growth, which develop from tutipotent germ cells, and differentiate to form elements of all three embryological layers : ectoderm, endoderm, and mesoderm. They mainly arise in gonads (testis, ovary) and on the midline of the body (pineal gland, base of the skull, mediastinum, retroperitoneal and sacrococcigeal).

Last updated : 01/30/2009