NCIt definition : A teratoma which may be cystic; it is composed entirely of well differentiated, adult-type
mature tissues, without evidence of fetal-type immature tissues (grade 0 teratoma).;
Alternative definition : NCI-GLOSS: A type of benign (not cancer) germ cell tumor (type of tumor that begins
in the cells that give rise to sperm or eggs) that often contains several different
types of tissue such as hair, muscle, and bone.;