Endometrial changes in women receiving oral contraceptives

Smooth muscle in the female pelvic peritoneum: a clinicopathological analysis of 31 women

AIM

To study the presence and morphological features of smooth muscle in the subcoelomic mesenchyme with the aim of establishing both a normal range for the female pelvis, and its possible relationship to endometriosis, diffuse peritoneal leiomyomatosis (LPD) and other forms of 'müllerianosis'.

METHODS

Seventy laparoscopically obtained pelvic peritoneal biopsies accessioned over a 16-month period were examined from 31 women clinically suspected of endometriosis. These biopsies were selected for the presence of assessable, appropriately oriented peritoneum, sufficiently distant from focal endometriosis to allow a presumption of 'normality'. The histological features and morphometric measurements of smooth muscle in these biopsies were documented. Pathological changes, where present, were recorded.

RESULTS

Focal endometriosis was identified in 28 (40%) of the biopsies, nine (12.9%) displayed other manifestations of 'müllerianosis', 11 (15.7%) showed focal chronic inflammation or fibrosis only, and 22 (31.4%) displayed no specific pathological changes. Of 70 biopsies, 52 contained smooth muscle within the subcoelomic mesenchyme, directly below the peritoneal mesothelium. Biopsies in which smooth muscle was identified were predominantly from the region of the uterosacral ligaments (16/18) and pelvic side wall (22/25). The biopsies without a smooth muscle layer were predominantly from the pararectal area (7/8) or the rectal serosa (2/4). Where present, smooth muscle varied in prominence, depth, thickness of the layer and organisation of muscle bundles. Patterns ranged from thin, widely spaced and wispy fibres to a more or less continuous band of either horizontally and/or vertically organised fibres. Both focal and diffuse arrangements were evident. 'Neovascularisation' was observed laparoscopically in some areas that corresponded with prominent smooth muscle development.

CONCLUSIONS

Smooth muscle occurs sufficiently frequently immediately beneath the peritoneum of the female pelvis, and with a sufficiently predictable anatomical distribution, to be regarded as a normal component of the microanatomy of this tissue in the patients studied.

Endometrial microstructure after long-term use of a 91-day extended-cycle oral contraceptive regimen

OBJECTIVE

To assess the effect on the endometrial microstructure of an extended-cycle oral contraceptive (OC) regimen containing ethinyl estradiol (EE) and levonorgestrel (LNG).

METHODOLOGY

Subjects received up to four cycles of a 91-day extended-cycle OC regimen (84 consecutive days of monophasic 30 microg EE/150 microg LNG followed by 7 days of placebo). Endometrial biopsies were performed prior to the initiation and at the completion of therapy. All endometrial samples were processed centrally and reviewed by three independent pathologists blinded to treatment groups.

RESULTS

Endometrial biopsies were performed in 50 women. In general, samples taken after completion of therapy with no further hormonal exposure demonstrated rapid return to normal endometrial cycling. In contrast, the majority of subjects still on active extended hormonal OC therapy at the time of biopsy had inactive or atrophic endometrium. No intravascular blood clots were observed in any of the specimens.

CONCLUSION

The endometrial findings observed in this cohort of women treated with a 91-day extended-cycle OC regimen for up to 1 year showed no significant pathology. Additionally, the endometrium reverted quickly to normal cyclic changes in those subjects who, after completing therapy, elected not to continue with hormonal contraception.

Myometrial hyperplasia in pediatric, adolescent, and young adult uteri

OBJECTIVES

To evaluate if myometrial hyperplasia is a congenital variation in myometrial differentiation, or an acquired structural disorder of the myometrium, this study evaluated whether myometrial hyperplasia was present in uteri of children, adolescents, and young adults.

METHODS

We studied 19 pediatric/young adult uteri in cases with no clinical history of uterine disease. Random photomicrographs at 100x, taken at 1, 5, and 10 mm beneath the endometrium, were assessed for increased cellularity and nucleus/cell ratio, as compared to normal myometrium in the outer third of the same uterus.

RESULTS

Myometrial hyperplasia was generally absent in prepubertal uteri, first appeared in adolescent uteri just beneath the endometrium, and was found at 5 mm depth only after age 18. It decreased with depth beneath the endometrium (P<0.05).

CONCLUSIONS

Myometrial hyperplasia is not a congenital anatomic variation in myometrial differentiation, but rather an age-related acquired structural variation. Its relationship to common adolescent symptoms of dysmenorrhea and anovulatory bleeding remains unknown and unexplored.

Atypical polypoid adenomyomas of the uterus

We performed a clinicopathological immunohistochemical, ultrastructural, and flow cytometric study on six cases of atypical polypoid adenomyoma of the uterus including one with an adenocarcinoma within it. The tumours occurred in nulliparous women aged 22-48 years (average, 33.0 years); three arose in the uterine corpus, and three in the endocervix. Histologically, they were composed of endometrial glands admixed with a stromal component of interlacing bundles of smooth muscle cells. The glands exhibited varying degrees of architectural and cytological atypia. Most of the stromal cells showed strong staining for HHF35, alpha-smooth muscle actin, and vimentin, and some cells contained desmin. Electronmicroscopy, in one case, confirmed the presence of a well-differentiated smooth muscle component. The stromal component may arise as a result of extensive metaplasia of endometrial stromal cells. Uninvolved endometrium showed ciliated cell metaplasia in three patients, and atypical complex hyperplasia in two. One patient had a well-differentiated adenocarcinoma of endometrioid type arising in an endocervical atypical polypoid adenomyoma. All tumours had a diploid DNA content and relatively small S phase fraction (average, 6.23%). The follow-up periods ranged from 4 to 42 months (average, 13.5 months), and all patients were alive and well. Although the histogenesis of atypical polypoid adenomyoma of the uterus remains uncertain, it is suggested that it may arise because of oestrogen-related factors.

Smooth muscle differentiation at endometrio-myometrial junction. An ultrastructural study

To determine whether myometrial smooth muscle is newly produced at the endometrio-myometrial junction (EMJ) of the adult uterus, we examined the ultrastructure of mesenchymal components at this site during the menstrual cycle and during early pregnancy. Cells having some features of smooth muscle were found among the usual endometrial stromal cells in every specimen examined. In the follicular phase of the menstrual cycle, such cells resembled myofibroblasts, but in the luteal phase and during early pregnancy, they had more distinct cytoplasmic filaments with dense bodies and dense plaques, and other fairly well developed characteristics of smooth muscle. The identification of smooth muscle-like cells at the EMJ in the adult uterus and the finding that their morphology changes into cells having many of the characteristics of smooth muscle cells during the luteal phase and early pregnancy, suggests that smooth muscle differentiation possibly occurs from multi-potential mesenchymal cells in the endometrial stroma.

[The stromal and myogenic sarcomas of the uterus (author's transl)]

Stromal sarcomas of the uterus generally originate as homologous tumors from endometrial stromal cells with fixed potentialities. They may be composed of one type of cell or of several types, or rarely they may consist only of endometrial granulocytes. From the same source but with a more favorable prognosis is endolymphatic stromatosis, which arises primarily in the myometrium but does not diffusely invade it, as the stromal sarcoma does. By contrast, heterologous malignant mesenchymal mixed tumors of the endometrium originate from Müllerian epithelium derived fro the mesoderm, and are therefore pluripotential. In this group we find rhabdomyosarcomas and chondroblastomas which have a very poor prognosis. The myogenic sarcomas are three times more common, and arise from smooth muscle cells of the myometrium or its blood vessels. The degree of nuclear pleomorphism may vary considerably, from normal to giant cell types, and may differentiate also as clear-cell myoblasts. They portend a somewhat more favorable prognosis than the stromal sarcomas.

Studies in mice on the mutagenicity of two contraceptive drugs

An experiment is described which tests for visible and invisible mutants in mice treated with four different doses each of the contraceptives Gynanovlar and Lyndiol. The results show that there is no reason to suppose that either substance has an appreciable mutagenic effect, expressed as an increase of antenatal and postnatal lethals or visibles. The substrain CBA/CagCam, used throughout, has an incidence of 0.27% of singly occurring abnormalities, mainly of the appendicular skeleton, which distinguishes it from the parent CBA strain and its axial variation described by Gruneberg (1963).

Pathologic effects of oral contraceptives

The pathologic effects of oral contraceptives have been described in this paper and in other reviews [1, 5, 23, 35, 44, 48, 59, 80, 103, 114]. Approximately 10 million women currently use oral contraceptives in the United States. These drugs are beneficial both to the users and for population control. It is their effect on the health status of women who take them that must continue to have well-organized investigation so that more meaningful conclusions concerning their safety will permit continued use. In some instances, the pathologic effects of oral contraceptives make it necessary that new methods of contraception be found. Intensive research in this area is needed and judiciuos use of oral contraceptives must be maintained. A national registry should be formed to record and investigate the cases of women who die or have adverse reactions while taking these agents. A registry might identify associations no previously known to exist in patients taking oral contraceptives. It would serve to concentrate the data in one area so that more material would be available for the study of pathogenetic mechanisms. It would heighten patient and physician awareness of the untoward effects and increase the responsibilities of the women who take them to monitor their own health.

The effect of enzymes upon metabolism, storage, and release of carbohydrates in normal and abnormal endometria

This paper presents preliminary data concerning the relationship of various components of glandular epithelium and effect of enzymes on metabolism, storage, and release of certain substances in normal and abnormal endometria. Activity of these endometrial enzymes has been compared between two groups: 252 patients with normal menstrual histories and 156 patients, all over the age of 40, with abnormal uterine bleeding. Material was obtained by endometrial biopsy or curettage. In the pathologic classification of the group of 156, 30 patients had secretory endometria, 88 patients had endometria classified as proliferative, 24 were classified as endometrial hyperplasia, and 14 were classified as adenocarcinoma. All tissue was studied by histologic, histochemical, and biochemical methods. Glycogen synthetase activity caused synthesis of glucose to glycogen, increasing in amount until midcycle, when glycogen phosphorylase activity caused the breakdown to glucose during the regressive stage of endometrial activity. This normal cyclic activity did not occur in the abnormal endometria, where activity of both enzymes continued at low constant tempo. Only the I form of glycogen synthetase increased as the tissue became more hyperplastic. With the constant glycogen content and the increased activity of both the TPN isocitric dehydrogenase and glucose-6-phosphate dehydrogenase in the hyperplastic and cancerous endometria, tissue energy was created, resulting in abnormal cell proliferation. These altered biochemical and cellular activities may be the basis for malignant cell growth.