Histologic analysis of endometriomas: what the surgeon needs to know

Objective: To evaluate by thorough pathologic analysis the histologic features of the endometrioma wall excised at laparoscopy. Design: Prospective series of consecutive patients. Setting: Tertiary care, university hospital. Patient(S): Fifty-nine patients with ovarian endometriomas. A total of 70 cysts were examined. Intervention(s):Patients underwent operative laparoscopy with the stripping technique for excision of the ovarian endometrioma. Main Outcome Measure(s): A thorough histologic examination was performed on the entire cyst wall specimen. Result(S): Histologic examination confirmed the endometriotic nature of the cyst in 100% of the cases. The inner wall of the endometrioma was covered by endometriotic tissue on 60% of the surface. The mean cyst wall thickness was 1.4 mm. The mean value of maximal depth of endometriosis penetration in the endometrioma wall was 0.6 mm. In 99% of the cases the maximal penetration of the endometriotic tissue was < 1.5 mm. Conclusion(s): In the present study, we demonstrate that the endometrioma wall contains endometriotic tissue in 100% of the cases. However, the endometriotic tissue may cover the inner cyst wall for a surface that varies between 10% and 98% of the entire wall (median value 60%). This tissue may reach a depth of 2 mm, but for most of the surface it does not penetrate > 1.5 mm. These histologic data may help the gynecologic laparoscopist select the surgical approach that maximally preserves healthy ovarian tissue.