Correlation between aromatase expression in the eutopic endometrium of symptomatic patients and the presence of endometriosis

OBJECTIVE: To investigate whether aromatase expression in the eutopic endometrium correlates with the presence and severity of endometriosis in patients with infertility and/or dysmenorrhea undergoing laparoscopy and hysteroscopy. PATIENTS: The study involved 106 patients of reproductive age with symptoms of dysmenorrhea and infertility. Sixteen endometriosis-free asymptomatic patients were used as a control group. METHODS: Concomitant laparoscopy and hysteroscopy was carried out in all cases. An endometrial biopsy was taken to determine aromatase p450 expression by immunohistochemistry. Endometriosis was staged according to the American Society of Reproductive Medicine classification. RESULTS: Endometriosis was diagnosed by laparoscopy in 92/106 symptomatic patients. In this group, aromatase expression was detected in the eutopic endometrium of 66/92 patients with endometriosis (72%) and in 13/14 (95%) patients in the symptomatic, endometriosis-free group (P = 0.09). Aromatase expression was not detected in any patients from the control group. In the endometriosis group, aromatase expression was detected in the eutopic endometrium of 28/45 patients (62%) with American Society of Reproductive Medicine classification stage 1 of the disease, in 11/14 patients (78%) with stage II, 14/20 patients (70%) with stage III, and in 12/13 patients (92%) with stage IV; however, the difference was only statistically significant between stages I and IV (P = 0.04). CONCLUSION: Aromatase expression in the endometrium was associated with the presence of dysmenorrhea and infertility irrespective of the presence of endometriosis. When endometriosis was present, however, there was a tendency for aromatase expression to be positively correlated with dysmenorrhea severity.