Endometriosis is observed in one out of every ten women in society, causing endometrial cells to be found outside their normal location in the body and proliferate in other locations, leading to fibrosis in the tissue due to the secretion of various factors from the cells. Additionally, the substances secreted by the cells can cause various other changes in the tissue besides fibrosis. Increased neurogenesis and neovascularization are among the primary changes, which occur as a result of the secretion of substances from the cells. Increased neovascularization, neurogenesis, and fibrosis in the tissue lead to the formation of nodular structures in the pelvic region, resulting in pain development in women. Nodular formations in the pelvic region due to endometriosis are especially observed in the rectovaginal space. Despite being small in size, they can induce increased neovascularization and neurogenesis even in healthy peritoneal tissue due to the microenvironment they create, leading to different clinical symptoms clinically. However, it is not known how far these changes occur around the endometriotic nodule in the presence of endometriosis. In this project, in patients operated on due to endometriosis, the density of nerve and vascular structures in the surgical margins of the peritoneal tissue excised along with the nodule, and the synthesis and release of chemical mediators causing pain (e.g., Bradykinin, Substance-P) are evaluated. The aim is to determine the minimum surgical margin where excision should be applied in surgery and to demonstrate any endometriotic changes that may exist in the tissues, even though they may appear macroscopically healthy.