Surgical management
Clinical indications
Indications for surgical excision of endometriomas include pelvic pain, infertility, and prevention and diagnosis of malignancy. Endometriomas may be excised prior to use of assisted reproductive technology.13–15 Medical therapy, such as oral contraceptives, can be used to reduce the size of endometriomas but does not improve fertility.3 Certain ovarian cancers are more common in women with endometriosis, and ovarian tumors are thought to develop in about 1% of ovarian endometriosis cases.1,12 Therefore, endometrioma excision may reduce the risk of malignancy. As with other ovarian cysts, large endometriomas may be excised to reduce the risks of rupture and torsion.
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To watch the authors perform laparoscopic excision of type I and type II endometriomas, click here
Approach
Laparoscopy is the preferred approach for endometrioma excision. Controversy exists regarding the ideal procedure: complete excision (with stripping of the cyst capsule) or drainage and ablation of the cyst wall. Compared with drainage and ablation, excision reduces recurrence of endometriomas; relieves dysmenorrhea, dyspareunia, pelvic pain, and other symptoms; and improves fertility.13,16 The recurrence rate may be as low as 5.8% with complete excision but is 90% with simple transvaginal aspiration.17,18 If not performed properly, however, cyst capsule stripping may damage nearby ovarian stroma and decrease the ovarian reserve.14 Some authors have advocated combining excision and ablation—performing cystectomy until there is no longer a clear plane between capsule and ovarian stroma and then ablating any remaining endometrial tissue.8
With type I and IIC endometriomas, we have seen the endometrial cyst wall infiltrating the ovarian stroma so deeply there is not always a definable plane. By contrast, type IIA and IIB endometriomas typically have a plane between the cyst wall and the ovarian cortex. In type II endometriomas, endometrial implants on the ovarian cortex infiltrate the plane of the cyst wall such that the juxtaposing lipomatous follicular cyst detaches with minimal intraoperative traction. Portions of type II endometriomas containing fibrosis and adhesions may become more difficult to peel off the cyst wall. For most endometriomas, at least 1 spot is difficult to peel off the ovary, and extra care must be taken at the hilum of ovary to avoid excising healthy ovarian cortex.4,5,7,8
Our surgical approach accounts for the described variations in type I and II endometriomas. Endometrial contents often spill as the endometrioma is dissected off neighboring structures. When possible, endometriomas should be aspirated and irrigated prior to cystectomy to avoid seeding the pelvis and abdomen with spilled endometriotic contents. We use hydrodissection, the injection of dilute vasopressin with a laparoscopic needle, to create a plane between cyst wall and ovarian stroma and strip the cyst capsule with laparoscopic graspers. Type I endometriomas adhere densely to the ovary. Given the presence of fibrosis and adhesions, the cyst is excised in a piecemeal fashion. Care is taken to remove any endometrial implants from the ovary while preserving as much of the ovarian tissue as possible.1
Type II endometriomas are larger cysts originating from the invasion of endometrial implants or type I endometrioma into functional cysts. The difficulty of capsule excision varies according to the extent of endometrial invasion. Type IIA endometriomas contain less than 10% endometrial tissue within the cyst capsule. Thus, the standard ovarian cystectomy stripping technique is successful in removing more than 90% of the cyst capsule. Special care is taken in stripping the residual small portion that involves the endometrial glands and stroma and adheres densely to the ovary.
The larger proportion of endometrial tissue present in type IIB and IIC endometriomas degrades the plane between the cyst capsule and the ovarian stroma, making excision more difficult. Similar to the type I excision, a piecemeal approach is often necessary. If complete stripping of the cyst capsule would result in extensive loss of healthy ovarian tissue, then electrocautery, plasma energy, or laser ablation can be selectively used to destroy focal areas of endometrial invasion. Complete ablation may be difficult, as the endometrioma wall can be up to 5 mm thick.19 For these thick-walled endometriomas, we recommend excision (vs ablation), which lowers the risk of endometrioma recurrence.
Related article:
Endometriosis and pain: Expert answers to 6 questions targeting your management options
Key takeaways
- Endometriomas are common adnexal masses in women affected by endometriosis and may exacerbate pelvic pain and impair fertility. Classification of endometriomas into type I and type II,depending on their etiology and characteristics, can guide minimally invasive surgical management.
- Type I endometriomas arise from invagination of endometrial implants on the ovarian cortex, resulting in dense fibrosis and adhesions. These lesions typically require piecemeal excision in order to completely remove the cyst capsule.
- Type II endometriomas result from invasion of endometrial tissue into preexisting functional cysts and are further subclassified by the proportion of cyst capsule containing endometrial tissue (IIA <10%, IIB 10% to 50%, IIC >50%).
- The difficulty of excising type II endometriomas correlates with the degree of endometrial invasion, with type IIA being relatively straightforward and type IIC being as challenging and piecemeal as type I.
- We generally favor complete excision rather than ablation of the cyst capsule, except for when excision would result in an unacceptable loss of healthy ovarian tissue.
Conclusion
Endometriomas, common adnexal masses in women affected by endometriosis, may exacerbate pelvic pain and impair fertility. Gynecologists should be prepared to excise endometriomas completely and exercise care in preserving as much of the ovarian stroma as possible. We classify endometriomas into 2 types: type I, which develop from invagination of endometrial implants in the ovarian cortex, and type II, which stem from invasion of functional cysts by endometrial implants or type I endometrioma. This distinction guides surgical management. We hope this article and its accompanying video will be helpful in guiding laparoscopic excision of type I and II endometriomas.
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