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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 ?
a fetoprotein was elevated in 3 cases with yolk sac tumors and one case with malignant teratoma.
Combined management of malignant teratoma of the testis.
The presence of neuroepithelial tubules would raise concern for malignant teratoma only if they were abundant, making up the bulk of the tumor The diagnosis of gastric teratoma as a benign lesion is very important, so that the affected infants will not be subjected unnecessarily to the treatments of malignant tumors.
Our case was the rarest case reported by us about the mature cystic teratoma with malignant differentiation to squamous cell carcinoma arising from mesocolon of sigmoid region with only one case reported in 2007 with malignant teratoma arising from mesentry of descending colon as per the MEDLINE Database (12).
Moreover, there were no cases of malignant teratomas, choriocarcinoma or other rarer tumours during the study period.

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