Histological assessment of impact of ovarian endometrioma and laparoscopic cystectomy on ovarian reserve

Aim: The rate of oocyte decline follows a biphasic pattern, characterized by acceleration between 32 and 38 years old. Ovarian reserve is also affected by external factors, including ovarian disease and iatrogenic damage. The aim of this study was to histologically evaluate the impact of ovarian endometriomas, laparoscopic cystectomy, and age on follicle reserve in healthy ovarian tissues and in surgically resected cyst walls. Material and Methods: Sixty-one patients were found to have ovarian endometriomas and 42 patients non-endometriotic cysts. A small amount of normal ovarian tissue was obtained during ovarian cystectomy. The follicles in normal ovarian tissue and resected cyst walls were histologically evaluated. Results: The density of follicles in ovarian tissues correlated with the age of the patients in both groups. In women aged <35 years, the relative density of follicles in healthy ovarian tissues was consistently lower in the endometriotic cyst group compared to the non-endometriotic cyst group, with the relative ratio at age 20, 30 and 35 years calculated to be 35.4%, 46.8% and 62.7%, respectively. There was no significant difference between the groups in patients over the age of 35. The resection rate of normal ovarian tissue in cystectomy specimen of the endometriosis group was significantly higher than in the non-endometriotic cyst group (P < 0.001). Conclusions: Our data suggest that ovarian endometriomas have a detrimental impact on follicle reserve in younger patients. Further, laparoscopic cystectomy for endometriomas may accelerate the rate of oocyte loss associated with aging.