PERITONEAL ENDOMETRIOSIS, OVARIAN ENDOMETRIOSIS, AND ADENOMYOTIC NODULES OF THE RECTOVAGINAL SEPTUM ARE 3 DIFFERENT ENTITIES

Objective: To review the histogenesis of peritoneal, ovarian, and rect ovaginal endometriotic lesions. Design: The comparison of morphologic, morphometric, and histochemical data observed in each type of lesion. Setting: A university hospital department of gynecology. Patient(s): Patients complaining of infertility or pelvic pain with laparoscopical ly proved endometriosis. Intervention(s): Laparoscopy was performed, a nd biopsy specimens from the endometriotic lesions were histologically studied. Result(s): Three types of endometriotic lesions must be cons idered: peritoneal, ovarian, and rectovaginal. Morphologic and morphom etric data show similarities between eutopic endometrium and red perit oneal lesions, suggesting that these lesions are the first stage of ea rly implantation of endometrial glands and stroma. After partial shedd ing, the red lesions regrow constantly. The shedding induces an inflam matory reaction, provoking scarification, and the lesions become black . The subsequent fibrosis leads to areas of white opacification that a re inactive. The pathogenesis of ovarian endometriomas is a source of controversy. Although there seems to be a consensus concerning the inv agination theory, there is still a contradiction between the implantat ion theory and the metaplasia theory. We recently showed that the meso thelium covering the ovary can invaginate into the ovarian cortex, pus hing back the primordial follicles. The presence of mesothelial invagi nation in continuum with endometriotic tissue suggests that metaplasti c histogenesis of ovarian endometriotic lesions occurs. Rectovaginal e ndometriotic nodules must be considered adenomyomas, consisting of smo oth muscle with active glandular epithelium and scanty stroma. Immunoc ytochemical results show poor differentiation and hormonal independenc e of these lesions and indicate a close relation with their mesodermal mullerian origin. Conclusion(s): Peritoneal, ovarian and rectovaginal endometriotic lesions must be considered as three separate entities w ith different pathogeneses. (C) 1997 by American Society for Reproduct ive Medicine.