**3. Endometriosis**

It is acknowledged that about 11% of all women population during reproductive age is affected by endometriosis (Buck Louis, Hediger et al. 2011). Endometriosis is a chronic benign gynecological disease which is characterized by the ectopic formation of endometrial stroma and glands mostly seen in pelvic peritoneum. However, it might be seen outside the pelvic peritoneum such as, pelvic viscera(Vercellini, Meschia et al. 1996), rectovaginal septum (Nisolle and Donnez 1997), pleura, abdominal wall, and even sometime in brain (Thibodeau, Prioleau et al. 1987). Briefly, the underlay mechanism is attachment of endometrial cells to the pelvic peritoneum, invasion into the mesothelium, and survival and proliferation of the ectopic endometrial cells. Endometriosis is usually diagnosed after symptoms such as pelvic pain, which might correlate with menstrual cycle, or infertility.
