obsolete germ cell and embryonal cancer teratoma https://www.malacards.org/card/teratoma ICDO:9080/1 SCTID:36591000119102 ONCOTREE:TT MEDGEN:21097 DOID:3307 MESH:D013724 UMLS:C0039538 A non-seminomatous germ cell tumor characterized by the presence of various tissues which correspond to the different germinal layers (endoderm, mesoderm, and ectoderm). It occurs in the testis, ovary, and extragonadal sites including central nervous system, mediastinum, lung, and stomach. According to the level of differentiation of the tissues which comprise the tumor, teratomas are classified as mature or immature. Mature teratomas are composed of well differentiated, adult-type tissues. Immature teratomas are composed of immature, fetal-type tissues. Testicular teratomas in children follow a benign clinical course. Mature ovarian teratomas without a fetal-type component have an excellent outcome. The prognosis of immature ovarian teratomas is related to the grade and stage of the tumor. NCIT:C3403 MONDO:0002601 GARD:0023184 teratoma nongerminomatous germ cell tumor