Endometrial hyperplasia

Hyperplasia of the endometrium is a diagnosis, very often used by both morphologists and clinicians-gynecologists. For the latter, it is convenient as a component of a detailed diagnosis and evidence that the necessary diagnostic procedure in the form of curettage of the uterine mucosa is performed and the diagnosis of "endometrial cancer" is excluded.

The biological originality of the endometrium is that this hormone-sensitive tissue is very dynamic in nature and has the ability not only to cyclically renew almost all of its cellular composition, but is also very sensitive to all changes in hormonal effects at the level of the whole organism. It should be emphasized that the expressed sensitivity of the endometrium to the hormonal influences of the internal environment of the body is peculiar not only to the mucosa of the uterine cavity in which it is vividly manifested, but also in all target tissues of the female reproductive system, which underlies the pathogenesis of hyperplastic changes, or, conversely, persistent organ hypoplasia.

When scraping the mucous membrane of the uterine cavity in patients with glandular hyperplasia of the endometrium, a large amount of soft, pink tissue is usually obtained. Foci of necrosis and hemorrhages can give fragments of scrapes a mottled appearance. When examining the removed uterus, one can see that the mucosa of the cavity is thickened to 1-2 cm. The endometrium surface is usually smooth, less often small-hulled or polypoid. On a cut, it is possible to distinguish between the cysts visible to the naked eye and a clear line of delineation between the endometrium and the myometrium.

When histological examination of mucosal scraping from the uterine cavity, the diagnosis of glandular hyperplasia of the endometrium usually does not cause difficulties. Glands of various shapes and sizes are defined. Along with the small glands there are large, cystlike, enlarged. They are lined with a highly prismatic epithelium with multi-row nuclei and clearly delineated apical edges of the cells. The nuclei are oval or somewhat elongated, rich in chromatin. Polychrome can be defined. The cytoplasm is usually basophilic and there is no secret in it, although slime can be detected in the lumen of the glands. Stromal cells are somewhat enlarged in volume, and their cytoplasm is often acidophilic. In glandular and stromal cells, there are often figures of mitosis, which indicates active proliferation of both glandular and stromal elements.

Hyperplasia of the endometrium causes a persistent and prolonged elevated estradiol in the blood or, at its normal level, the absence of cyclic fluctuations and a sufficient level in the blood of progesterone, which are two important components of the menstrual cycle. If we turn to the pathophysiological causes that lead to the phenomenon of increased estrogenic effects on the endometrium, then the most frequently occurring disorders should be mentioned here:

• 1) persistence or atresia of follicles in the ovaries;
• 2) hyperplastic processes in the ovaries, causing increased secretion of estradiol (follicular cysts, hypertrophy of the teka-tissue and hilar cells in the ovaries, sclerokinoznye ovaries and feminizing tumors of the ovaries).

To study the relationship between hyperplastic processes in the ovaries and their effect on the frequency of the development of endometrial hyperplasia, we, together with Ya. V. V. Bohman, VA Pryanishnikov and OF Chepik (1979), examined clinical data and operational macro- and micro-preparations in 200 patients with hormonal-active processes in the ovaries (tecomies, granulosa cell tumors, ovarian fibroids, Brenner's tumors and sclerocystic ovaries). All patients studied the state of the endometrium. As a result, 115 (57.5%) of 200 patients had different degrees of endometrial hyperplasia; atypical hyperplasia was detected in 18 (9%), endometrial cancer - in 23 (12.5%) patients. It is noteworthy that endometrial polyps of "interest" in increased estrogenic influence for their growth have not been shown. They were identified in 11 (5.5%) women.

Another important reason for the increased estrogenic effect on the endometrium is the change in the metabolism of steroid hormones in adipose tissue, namely its ability, due to the aromatase enzyme present in it, to convert the estrogen precursors (androstenedione) to estrone. I must say that in a woman with a pronounced fat mass and postmenopause for more than 5 years, this process of "peripheral" estrogen formation is essentially the only one, since the endocrine function of the ovaries is stopped by this time.

The macroscopic picture of atypical endometrial hyperplasia does not have specific features. They can be found both among ordinary and even thin endometrium, and among thickened or polypoid endometrium.

For a microscopic picture of atypical hyperplasia of the endometrium, a significant predominance of glandular elements over the stromal ones is observed, which is not observed in the case of ordinary glandular hyperplasia of the endometrium. Atypical hyperplasia of the endometrium may be weak, moderate and severe. Typical for all degrees of atypical hyperplasia is a very close arrangement of glands with narrow stroma interlayers between them. The severity of atypia is manifested in the degree of changes observed in the structure of the glands and the epithelium lining them. Usually such distribution of glands at an atypical hyperplasia of an endometrium designate as an arrangement of "back to a back".

The glands lose the usual regularity of the normal endometrium, they are extremely diverse in size and shape. The epithelium lining the gland consists of larger cells than in ordinary glandular hyperplasia. The cytoplasm is usually well developed and can be basophilic, light translucent, and with pronounced degrees of atypical hyperplasia, acquire an eosinophilic color. The core is usually oval or somewhat elongated. They can be either hyperchromic or hypochromic, and the pale coloration of the cores is more often observed with more pronounced degrees of atypical endometrial hyperplasia.

Particular attention should be paid to the degree of multi-row arrangement of nuclei, which increases with the growth of atypia. It should be borne in mind that the normal endometrial glands, even in the proliferative phase, are lined with a single layer of cells with single-rowed nuclei (Koss, 1968). With the usual glandular hyperplasia, the number of nuclei takes place, but it is usually not as pronounced as in atypical hyperplasia, in which, along with this, the polarity of the location of the nucleus is disrupted, and they become polymorphic in the case of pronounced degrees of its development.

At weak degrees of atypical hyperplasia of the endometrium, the stroma can be cytogenic, but more often the cells become elongated, folded into narrow bundles among closely located glands.

Expressed degrees of atypical endometrial hyperplasia, especially in the study of scrapings, it is often difficult, and sometimes almost impossible to distinguish from highly differentiated forms of endometrial cancer.

Many proposals were made on the classification of hyperplastic endometrial processes, especially before 1994. But in 1994, WHO finally adopted a morphological classification that fully meets the needs of many researchers and clinicians, which has allowed it to be retained to date as an international document.

In general, it can be determined that endometrial hyperplasia is a sequence of changes in the architecture of the glandular component, classified by increasing. In this case, the main criteria for assessing the changes occurring are the structure of endometrial glands (structural changes) and changes in cell nuclei (cellular changes).

It is appropriate to cite the complete classification of hyperplastic changes in the endometrium, developed by WHO experts and published under its auspices in 2003 (Lyon). It should be noted that this classification is not a result of laboratory research of a narrow circle of specialists, but was developed on the basis of a large number of clinical comparisons involving prominent specialists on this issue (for example, the Kurman and Norris groups that directly participated in the development of this classification).

Like any classification, it is rather conditional and distributes hyperplastic changes in the endometrium into four groups.

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