Endocrine dependency of endometriosis: an ultrastructural study

The comparison of the ultrastructural features of endometriotic implants in 96 patients before and after suppressive therapy by danazol showed that the glands of the ectopic endometrium had a wide range of morphologic development. In about one-third of the pretreatment biopsies significantly different ultrastructural patterns were observed in the same specimen, ranging from poorly to highly differentiated endometrial glands. Adequate morphological changes during the menstrual cycle were found in implants only in 14 patients during the proliferative phase, but adequate, homogeneously performed secretory changes were completely missing during the luteal phase. Besides incomplete or delayed secretory changes the majority was proliferative rather than secretory. After 6 months of endocrine suppression laparoscopic biopsies of endometriosis were repeated, and the ultrastructural findings lead to three conclusions. 1. Poorly differentiated endometriotic foci do not respond to danazol. 2. Endometriotic implants consisting of highly differentiated epithelium with adequate cyclic variations respond well to danazol and disappear in nearly 80% of cases. 3. In endometriosis with mixed areas consisting of various degrees of glandular differentiation the hormonal suppression can eliminate endometriotic implants or arrest them at a proliferative stage. If the morphological appearance of the ectopic implants depends not simply upon the endocrine stimulus, but primarily on the degree of differentiation and maturity of the cell, then perhaps cyclic modulation is only a secondary phenomenon, and hormones play only a secondary role in therapy. If this hypothesis is correct, only complete elimination of endocrine influence can cure endometriosis. Transient or incomplete suppression may lead only to partial regression.