Canadian Medical Guide > Diseases > Neoplasms > Neoplasms by Histologic Type > Neoplasms, Germ Cell and Embryonal Terms and Definitions




Neoplasms, Germ Cell and Embryonal

Medical Definition: Neoplasms composed of primordial germ cells of embryonic gonads or of elements of the germ layers of the embryo. The concept does not refer to neoplasms located in the gonads or present in an embryo or fetus.
Guide Notes: neoplasms composed of germ cells or embryonic tissue, NOT neoplasms located in germ cells or embryonic tissue; do not confuse with GERM CELL TUMOR see GERMINOMA; coord IM with precoord organ/neopl term (IM); DF: NEOPL GERM CELL
Also Called: Neoplasms, Embryonal,Neoplasms, Embryonal and Mixed,Neoplasms, Germ Cell,Germ Cell Cancer,Cancer, Embryonal,Cancer, Embryonal and Mixed
Neoplasms, Germ Cell and Embryonal Categories.
Canadian Medical Guide Definition Carcinoma, Embryonal - A highly malignant, primitive form of carcinoma, probably of germinal cell or teratomatous derivation, usually arising in a gonad and rarely in other sites. It is rare in the female ovary, but in the male it accounts for 20% of all testicular tumors. (From Dorland, 27th ed & Holland et al., Cancer Medicine, 3d ed, p1595)
Canadian Medical Guide Definition Chordoma - A malignant tumor arising from the embryonic remains of the notochord. It is also called chordocarcinoma, chordoepithelioma, and notochordoma. (Dorland, 27th ed)
Canadian Medical Guide Definition Germinoma - A malignant neoplasm of the germinal tissue of the gonads, mediastinum, or pineal region such as seminomas. The degree of differentiation to form adult cell types varies. The germ cell tumors of infants and children reflect the transformation of primordial cells that have failed to migrate to their predestined location. Germinomas are uniform in appearance, consisting of large, round cells with vesicular nuclei and clear or finely granular eosinophilic-staining cytoplasm. (Stedman, 265th ed; from DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, pp1642-3)
Canadian Medical Guide Definition Mesonephroma - A rare tumor of the female genital tract, most often the ovary, formerly considered to be derived from mesonephric rests. Two varieties are recognized: (1) clear cell carcinoma, so called because of its histologic resemblance to renal cell carcinoma, and now considered to be of muellerian duct derivation and (2) an embryonal tumor (called also ENDODERMAL SINUS TUMOR and yolk sac tumor), occurring chiefly in children. The latter variety may also arise in the testis. (Dorland, 27th ed)
Canadian Medical Guide Definition Neuroectodermal Tumors - Malignant neoplasms arising in the neuroectoderm, the portion of the ectoderm of the early embryo that gives rise to the central and peripheral nervous systems, including some glial cells.
Canadian Medical Guide Definition Teratocarcinoma - A malignant neoplasm consisting of elements of teratoma with those of embryonal carcinoma or choriocarcinoma, or both. It occurs most often in the testis. (Dorland, 27th ed)
Canadian Medical Guide Definition Teratoma - A true neoplasm composed of a number of different types of tissue, none of which is native to the area in which it occurs. It is composed of tissues that are derived from three germinal layers, the endoderm, mesoderm, and ectoderm. They may be solid or cystic and are classified histologically as mature, immature, and malignant. (From Dorland, 27th ed & DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1642)
Canadian Medical Guide Definition Trophoblastic Neoplasms - Trophoblastic growth, which may be gestational or nongestational in origin. Trophoblastic neoplasia resulting from pregnancy is often described as gestational trophoblastic disease to distinguish it from germ cell tumors which frequently show trophoblastic elements, and from the trophoblastic differentiation which sometimes occurs in a wide variety of epithelial cancers. Gestational trophoblastic growth has several forms, including HYDATIDIFORM MOLE and CHORIOCARCINOMA. (From Holland et al., Cancer Medicine, 3d ed, p1691)

Neoplasms, Germ Cell and Embryonal Medical Definitions and Terms

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