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A true neoplasm composed of bizarre and chaotically arranged tissues that are foreign embryologically as well as histologically to the area in which the tumor is found.



a neoplasm occurring in man and animals that results from the impaired embryonic development of tissues. Found mainly in children and adolescents, it is localized in the sex glands and occasionally in other organs and parts of the body. A teratoma generally consists of different types of tissue, including connective, epithelial, muscular, and neural tissue, and may include such differentiated derivatives of these tissues as teeth and hair.

The most complex teratomas in terms of composition and structure are those that have developed from early blastomeres or from primary sex cells that are totipotential, or able to develop into any type of body tissue. Teratomas that arise at later stages of embryonic development (after gastrulation) are limited in composition by the formative potential of the embryonic germ layer or organ from which the teratomas originate. Simple, relatively benign teratomas are distinguished from teratoblastomas— malignant tumors composed of tissues of embryonic structure and lacking a tendency to differentiate. Simple teratomas are also distinguished from teratoids—developmental defects that are not tumors but that may develop into tumors. Teratomas may become carcinomas or sarcomas.


Klinicheskaia onkologiia detskogo vozrasta. Edited by M. V. Volkov. Moscow, 1965. (Contains bibliography.)
References in periodicals archive ?
Mature teratomas have been commonly reported in the ovaries, testes, and mediastinum, and are less commonly reported to involve various midline locations, including the sacrococcygeal area.
The most common sites of teratomas of the head and neck are the cervical region and the nasopharynx.
26% of mature teratomas contain calcified elements.
showed that the formerly peach-sized tumor, a rare form known as a mature teratoma, has shrunk more than 40 percent from its peak, said Dr.
Teratoma was found to be Type II with some intrapelvic extension and was encroaching near the rectal wall which was carefully dissected without any injury.
Teratomas also exhibited higher ORs at the highest quartile (2nd quartile: OR = 1.
11) Differentials of fat-containing mediastinal lesions are lipoma, liposarcoma, mediastinal lipomatosis, teratoma, diaphragmatic hernias, extramedullary erythropoiesis, lipoid pneumonia, lipoblastoma and cardiac liposarcomas.
This tumor possesses the histopathologic features of both teratomas and carcinosarcomas.
Some reports describe mixed hepatoblastoma and teratoma as combined tumors that probably represent teratoid hepatoblastomas.
Although the imaging appearance of dermoid tumors is characteristic, several other intracranial lesions must be considered in the differential diagnosis, such as epidermoids, teratomas, lipomas, craniopharyngiomas, and occasionally arachnoid cysts.
Similar to prepubertal teratomas, they are well-circumsized, benign tumors that mostly do not metastase.
Increased serum SCCa values have also been linked with benign diseases, including sinonasal inverted papillomas, ovarian cystic teratomas, and various skin disorders (12-15).