CHAPTER 103 Teratomas Shilpa

Introduction The term teratoma, derived from the Greek teraton meaning “a monster”, was coined by Virchow in 1869 for a tumour originating in the sacrococcygeal region. Teratomas are composed of multiple tissues foreign to the organ or site in which they arise. Although teratomas are sometimes defined as having the three embryonic layers (endoderm, mesoderm, and ectoderm), recent classifications also include monodermal types. The term germ cell tumour (GCT) is also frequently used to describe these tumours, although this term encomprises a larger group including the mature and the immature teratomas, germinomas, embryonal carcinomas, yolk sac tumours, and choriocarcinomas. The germ cell tumours may arise in the gonads or in extragonadal sites, including the brain, face, neck, mediastinum, retroperitoneum, and sacrococcygeal region.