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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 ?
Both need to be distinguished from the usual teratoma of the adult testis because they are uniformly benign, whereas the usual postpubertal teratoma may have associated metastases of either teratomatous or nonteratomatous germ cell tumors.
Dermoid, epidermoid, and teratomatous cysts of the tongue and the floor of the mouth.
One quarter of cases was found to be associated with teratomatous component.
Histologically they comprise seminomatous and/or teratomatous elements.
Young et al (10) have identified epidermoid cysts, some in concert with small Walthard rests, but in the absence of any other teratomatous features.