Observations on the pathology and spread of endometriosis based on the theory of benign metastasis

Abstract

Normally, benign endometrium is confined to the uterine cavity where it undergoes cyclical homeoplasia. The spread of benign endometrium is essentially the same as for endometrial carcinoma and has been summarized in Fig. 10. It governs the location of the various genital, extragenital, peritoneal, and extraperitoneal lesions of endometriosis. In addition to cyclical homeoplasia, the composite theory of benign metastasis for endometriosis includes: 1.1. Direct extension either into the lymphatics or blood vessels of the myometrium or between the muscle bundles, producing adenomyosis uteri. Direct extension may also take place into the endosalpinx forming a nidus of endometrium for the exfoliation of cells.2.2. Exfoliation and implantation of endometrial cells at menstruation, during curettage, or from a nidus in tube to produce lesions on peritoneal surfaces.3.3. Lymphatic spread with involvement of lymph nodes and adjacent organs.4.4. Venous spread in uterus and tubes and hematogenous metastasis to distant organs such as the kidney.5.5. Secondary lesions from foci already established along the above channels.The composite theory of benign metastasis for the spread of endometriosis is based on an experience with 1,371 patients during the past 17 years, or a clinic incidence of 5.61 per cent. During the past four years, 763 patients were observed, or more than one-half of the total number, giving an incidence of 9.91 per cent. This apparent increase coincides with the tendency toward smaller families, widespread use of contraception, fewer cervical dilatation and fewer uterine suspension operations, and more intravaginal tampons during menstruation.Not every patient with endometriosis will exhibit the entire pattern of dissemination since there are other related factors including: age at onset, hormone balance, cervical stenosis, retroversion, intravaginal tampons, sterility, parity, tissue resistance and reaction, duration of the disease, type of pelvic surgery (conservative, castration), radiation, testosterone, and pregnancy. Young patients may require a dilatation and curettage, excision of pelvic lesions and adhesions, conservation of ovarian function, and uterine suspension, after which they are urged to conceive at once. Pregnancy is the best prophylactic and curative treatment for endometriosis, since it interrupts the cyclical homeoplasia during which time the endometrium lies dormant. Each pregnancy reduces the period of growth for the endometrium by approximately 12 months.The incidence of further spread or recurrence after conservative surgery depends on the original extent of the process, the success of the operation, and the number of pregnancies. In older women, total hysterectomy and bilateral salpingo-oophorectomy may become the procedure of choice, rather than castration by irradiation since the latter may stimulate the endometrium to develop adenocarcinoma, as has been observed in several patients. Furthermore, it has been shown1 that endometrial carcinoma occurs with greater frequency in patients with endometriosis.