Introduction: The presence of epithelial cells in the peritoneal cavity and within the myometrium was described during the second part of the 19th century and was given the name “adenomyoma”. Then, with the identification of peritoneal endometriosis in the 1920s, adenomyosis became a separate nosological entity. For decades, the two abnormalities have been considered separate benign proliferative conditions of the female reproductive tract with a different clinical profile. More recently, however, evidence has been accumulated indicating that these two diseases have in common an endometrial dysfunction involving both eutopic and heterotopic endometrium causing a reaction in the inner myometrium. It therefore seems that adenomyosis and endometriosis share a common origin in an abnormal eutopic endometrium and myometrium. ADENOMYOSIS refers to the benign invasion of the uterine musculature by the endometrial mucosa. ENDOMETRIOSIS refers to presence of ectopic benign invasive endometrial tissue outside the uterus. Objective: In this study we show, results of application of fourth immunohistochemical stain method using endothelial marker of stromal cells (CD 10), oestrogen and progesterone receptor (ER and PR), cells proliferation marker (Ki 67) and marker of macrophages (CD 68). A marker that is simple to measure could help clinicians to diagnose (or at least exclude) interna or externa endometriosis; it might also allow the effects of treatment to be monitored. If effective, such a marker or panel of markers could prevent unnecessary diagnostic procedures and/or recognize treatment failure at an early stage. Design: We studied hematoxylin–eosin sections and immunoreactivity of CD 10, CD 68, Ki 67, ER, PR in both cases diagnosed as compatible with endometriosis. Recent progress in immunohistochemistry has found that CD10 and Ki 67 could be important markers for endometrial tissue. Although CD10 is known as a common surface marker of acute lymphoblastic leukemia, it is also expressed in epithelial cells including renal tubular and glomerular cells, breast and salivary gland myoepithelium, prostatic glandular epithelium, and pulmonary alveolar lining cells. However, in endometriosis, CD10 is not expressed in glandular epithelial cells, but in stroma. The oestrogen and progesterone receptors, reveal the mechanism of the disease, and determine the most sensitive procedure for detecting an endometrial tissue. Results: Therefore, other markers should be considered for exploring endometrial tissue. The analyses were summarized as follows: 1) the progesterone receptor antibody showed the strongest positive staining in the nucleus of the stromal cells in comparison to the oestrogen receptor, CD10, and Ki 67; 2) the CD10 antibody had the highest specificity in the cytoplasm of the stromal cells; and 3) the Ki 67 antibody had the widest distribution in both the endothelial and stromal cells. Strong positive staining in the nucleus of both cells against the antibodies of the oestrogen and progesterone receptors suggested that the tumor had a hormonal responsiveness related to the menstrual cycle the same as did a uterine endometrium. The CD10 antibody had a strong affinity with the cytoplasm of the stromal cells indicating the potential of a diagnostic tool for differentiating from other tumors of epithelial origin. Conclusions: Peritoneal endometriotic lesions and the uterine adenomyosis have a similar immunohistochemical profile. Both endometriotic and endometrial glands are positive for CD 10, Ki 67, ER, PR, but not for CD 68. Endometriotic stroma stains positively with endometrial–type stroma markers CD10, Ki 67 and oestrogen and progesterone receptors for the nucleus of the stromal cells. The combination of the oestrogen or progesterone receptor antibody for the nucleus and the CD10 or Ki 67 antibody for the cytoplasm could enhance the accuracy of diagnosis for endometriosis.Endometriosis is a mystery tour as it requires decision making at every stage by the physician and the patient. Endometriosis still stand as one of the most-investigated disorders in gynecology. So is one of the highest priorities for research.