EMBRYONAL CANCER

From Big Medical Encyclopedia

EMBRYONAL CANCER (Greek embryon uterine fruit, germ; a synonym a teratoblastoma) — a malignant germinogenny tumor.

Germinogenny tumors develop from totipotent (property to be a source of development of any body tissues) the highly specialized germinogenny epithelium of gonads capable to be exposed to a somatic and trophoblastic differentiation and to be a gistogene-tichesky source

of tumors, various on a structure: seminomas

of a small egg (see the Seminoma), dysgermoinomas of an ovary (see the Dysgermoinoma), embryonal cancer, horionepiteli-ohms (see. A trophoblastic disease), poliembrioma, teratomas (see), and also the tumors combining structures of these new growths (a tumor more than one gi-table. type according to WHO classifications). Embryonal cancer, as well as other germinogenny tumors, can initially be localized in ovaries and testicles, and also to be located ekstragonadno — in presak-ralny area, retroperitoneal space, a mediastinum, in vascular textures of ventricles of a brain, in the field of a pinus, in a nasal cavity and jaws. Developing of a tumor out of gonads is explained by a delay of a germinogenny epithelium a way of its migration from a wall of a vitellicle to the place of laying of gonads in the period of embryonic development (4 — the 5th week).

The etiology of embryonal cancer is not known. However there are instructions on a number of the factors promoting development of a tumor, the main of to-rykh should be considered genetic and existence of a malformation of gonads, in particular a cryptorchism (see). The role of a genetic factor is confirmed by frequent developing of tumors at brothers and sisters, at monozygotic, identical twins, and also in the second small egg.

Macroscopically the tumor has the form of a node with a clear boundary. It is formed by softish gray-white fabric, in a cut the centers of a necrosis and hemorrhages often meet, small cysts are sometimes visible.

Microscopically distinguish E. river of adult type, youthful type and poliembriy. Each of the listed tumors represents quite certain klinikomorfologichesky unit and is included in the International histologic classifications of tumors of testicles (1973) and ovaries (1977) as a separate nosological form. As a rule, these tumors are combined with each other, and also with a mature or unripe teratoma, a seminoma, horionepiteliomy.

AA. the river of adult type (embryonal cancer of somatic type) microscopically consists of the large, polygonal cells with round or oval kernels containing sometimes several kernels and light vacuolated cytoplasm. Mitoses can meet. Tumor cells create small papillary, tubular and ferruterous structures that is considered a sign of an epithelial differentiation. The stroma can very scanty be, as a rule, presented by edematous, friable mesenchymal fabric of embryonal type. There can be sites of the hyalinized connecting fabric. Most often E. the river of adult type is observed in testicles at men aged from 20 up to 30 years and differs in high degree of a zlokachestvennost.

AA. river of youthful type (synonym: the tumor of a vitellicle, a tumor an endoderm of a lny sine, embryonal cancer of extraembryonic type, an adenocarcinoma of a youthful small egg, an orkhioblastom) microscopically consists of the cells of the cubic, cylindrical, often flattened form reminding an endothelium.

In tumor cells, and also in a stroma CHIC-positive hyaline little bodies can be found (see CHIC reaction). The stroma is presented by a friable primitive mesenchyma, in a cut the cells reminding smooth muscle are sometimes visible. The tumor most often occurs in testicles at boys aged from 31/2 months up to 3 years and has rather favorable current.

Poliembrioma meets seldom. Microscopically consists of so-called embrioidny little bodies (the structures reminding on a structure an embryo at 1 — 2 weeks pregnancy) and it is regarded by many researchers as an early phase of development of embryonal cancer.

Embryonal cancer, especially adult type, differs in high degree of a zlokachestvennost. Most early metastasises appear in retroperitoneal (parietal), inog-4 yes in supraclavicular limf, nodes and limf, nodes of a mediastinum. Hematogenous metastasises appear in lungs and a liver more often. In metastasises the tumor can keep the initial structure. However along with structures E. rubles in metastasises are often visible elements of a teratoma and (or) a horionepitelioma. This phenomenon is explained by features of a histogenesis of this new growth.

Treatment consists in operational removal of primary node of a tumor and regional limf, nodes with carrying out in the subsequent chemotherapy (see Chemotherapy of tumors).

The forecast depends on type E. river; the least favorable forecast at E. river of adult type.

Prevention is not developed, however in emergence E. the river should consider a role genetic, a factor.

Embryonal cancer of a small egg and an ovary — see the Small egg, tumors; Ovaries, tumors.

Bibliography: Blochin H. N and Pe

re in d h and to about in and N. I. Himioterapiya of tumoral diseases, M., 1984; Pathoanatomical diagnosis of opu-salts of the person, under the editorship of N. A. Krayevsky I other, page 298, M., 1982; The Guide to cytologic diagnosis of tumors of the person, under the editorship of A.S. Petrova and M. P. Pto-hov, page 108, M., 1976; Serov S. F. and Scully R. E. Histologic classification of tumors of ovaries, M., 1977; Gynecologic oncology, ed. by M. Copp-leson, p. 680, Edinburgh a. o., 1981; M about s-tof i F. K. a. Price E. B. Tumors of the male genital system, Washington, 1973; M about s t about f i F. K. a. S o-b i n L. H. Histological typing of testis tumorers, Geneva, 1977; Scully R. E. Tumor of the ovary and maldeveloped gonads, Washington, 1979; T e i lum G. Special tumors of ovary and testis and related extragonadal lesions, Copenhagen, 1971.

H. H. Pokrovsk.

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