Endometriosis: Management of ovarian endometriomas

INTRODUCTION — An ovarian endometrioma is a cystic mass arising from ectopic endometrial tissue within the ovary. It contains thick, brown, tar-like fluid, which may be referred to as a "chocolate cyst." Endometriomas are often densely adherent to surrounding structures, such as the peritoneum, fallopian tubes, uterus, and bowel. This topic will review management of ovarian endometriomas.

Related information on the presentation, diagnosis, and management of endometriosis, as well as information on other types of adnexal masses, is available in related content.

●(See "Endometriosis in adults: Pathogenesis, epidemiology, and clinical impact".)

●(See "Endometriosis: Treatment of pelvic pain".)

●(See "Approach to the patient with an adnexal mass".)

In this topic, when discussing study results, we will use the terms "women" or "patients" as they are used in the studies presented. We encourage the reader to consider the specific counseling and treatment needs of transgender and gender diverse individuals.

BASELINE EVALUATION — The baseline evaluation for individuals with suspected endometriomas includes:

●Assess symptoms

●Perform pelvic examination to correlate symptoms with examination findings

●Perform pelvic imaging, typically with transvaginal ultrasound

●Evaluate malignancy risk

●Discuss future fertility plans

●Consider importance of ovarian reserve

Assess symptoms — Endometriomas can be asymptomatic or cause symptoms of pain, dyspareunia, and/or mass effect. The degree of impact on ability to perform routine activities and quality of life guide treatment options. The clinical presentation of patients with endometriosis in general is discussed in related content. (See "Endometriosis: Clinical features, evaluation, and diagnosis", section on 'Clinical features'.)

Perform physical examination — Pelvic examination is performed to assess the correlation between specific symptoms and physical findings. (See "Endometriosis: Clinical features, evaluation, and diagnosis", section on 'Physical examination'.)

Perform imaging — Imaging studies are performed to confirm a likely endometrioma, exclude findings suggestive of malignancy, and assess for change over time. While definitive diagnosis of an endometrioma requires histologic evaluation of a surgical specimen, imaging findings have high sensitivity and specificity for detecting an endometrioma. (See "Endometriosis: Clinical features, evaluation, and diagnosis", section on 'Imaging'.)

●Ultrasound imaging – Ultrasound is typically the first-line imaging study for evaluating an adnexal mass (image 1A-B) [1]. The sensitivity and specificity for diagnosing an endometrioma are greater than 90 percent and ultrasound is generally available and lower in cost than computed tomography (CT) or magnetic resonance imaging (MRI) imaging [2,3]. Individuals with an indeterminate adnexal mass may benefit from repeat interval imaging (eg, hemorrhagic cyst) or MRI for further delineation (eg, concern for malignancy) [3]. (See "Approach to the patient with an adnexal mass", section on 'Diagnosis'.)

Findings suggestive of an endometrioma include an avascular, thick-walled cystic mass that contains material with a homogenous low-level echo pattern (ie, ground-glass appearance) (image 1A-C) [1,4]. The lesion may be uni- or multilocular; multilocular lesions can have varying levels of echogenicity. Septations should be smooth and there should be no solid elements. Cyst size is measured in three orthogonal planes [5]. Serial images can assess subsequent changes in size or appearance. (See "Endometriosis: Clinical features, evaluation, and diagnosis", section on 'Findings'.)

●Magnetic resonance imaging (MRI) – MRI can be useful if the initial ultrasound findings are indeterminate for endometrioma or to evaluate for additional lesions, bladder or bowel involvement, and/or the presence of potential adhesions that may make the surgery more complex [2,3,6]. The number of adnexal lesions that remains with an indeterminate diagnosis drops from 20 to 25 percent with ultrasound to 5 to 7 percent with MRI [7-13]. (See "Endometriosis: Clinical features, evaluation, and diagnosis", section on 'Modalities'.)

Evaluate malignancy risk — While the overall risk of malignancy within an endometrioma is low (typically less than 0.8 percent), risk of malignancy is increased with larger lesions (>9 cm) and increasing patient age (>45 years) [14]. Endometriosis of the ovary is also associated with a small increased risk of transformation to ovarian cancer; the most common histologies are clear cell and endometrioid [15-17]. For these reasons, endometriomas are removed if they have an atypical appearance on imaging studies and/or other concerning features (eg, enlarging size, nodularity), occur in patients of older age, or occur in patients with an elevated baseline risk of ovarian cancer [18].

●(See "Endometriosis in adults: Pathogenesis, epidemiology, and clinical impact", section on 'Ovarian cancer risk'.)

●(See "Genetic testing and management of individuals at risk of hereditary breast and ovarian cancer syndromes".)

Serum CA 125 level is generally not helpful in excluding malignancy because the level may be increased with endometriosis, endometriomas, and other benign conditions, in addition to ovarian cancer (table 1) [19,20]. (See "Adnexal mass: Role of serum biomarkers in diagnosing epithelial carcinoma of the ovary, fallopian tube, or peritoneum".)

Discuss future fertility plans — Excision of endometriomas improves spontaneous pregnancy rates in subfertile individuals but has no impact when advanced reproductive technologies such as in vitro fertilization (IVF) are employed [21]. Endometrioma resection has not been shown to improve IVF/intracytoplasmic sperm injection (ICSI) outcomes and therefore is not advised for this indication [22-25]. Patients planning IVF or ICSI should consider endometrioma resection only if they are having bothersome symptoms (eg, pain or mass), to exclude malignancy, or if the size and/or position of the endometrioma would preclude follicle aspiration during a planned future IVF cycle [25]. (See "Endometriosis: Treatment of infertility in females".)

●In one study of women with subfertility and endometriomas, excision of the endometrioma was associated with an increased spontaneous pregnancy rate compared with those who had cyst wall ablation only [21].

●Conception and pregnancy rates are not improved when endometriomas are treated with hormonal treatments such as danazol or gonadotropin-releasing hormone (GnRH) agonists [26,27]. Hormonal medical therapy is discussed below. (See 'Mild symptoms' below.)

Consider importance of ovarian reserve — Ovarian reserve, as measured by serum anti-müllerian hormone (AMH), is decreased in patients with endometriomas >3 cm in diameter and further decreased if the endometrioma is surgically removed [28]. While AMH level does not predict the probability of natural conception, it does predict live birth following IVF. Therefore, the decision to proceed with ovarian surgery requires a careful discussion with the patient regarding the impact on ovarian function. AMH levels are only one marker of ovarian reserve and must be assessed within the entire clinical context, such as patient age; more information on ovarian reserve is presented separately. (See "Female infertility: Evaluation", section on 'Assessment of ovarian reserve'.)

●Impact of endometrioma – Endometrioma has been associated with reduced AMH levels and greater AMH decline over time [29,30]. In a study comparing AMH levels in 40 patients with endometrioma >3 cm with 40 age-matched control individuals without endometriomas, those with endometriomas had lower median AMH levels at study recruitment (2.83 versus 4.42 ng/mL) and greater AMH decline over six months (26 versus 7 percent) [30]. Although the endometrioma may reduce AMH levels and the number of follicles recruited in the ovary by exogenous follicle-stimulating hormone (FSH) stimulation, endometriomas do not appear to negatively impact pregnancy or live birth rates after IVF [31-33]. However, the reduction in follicle count may negatively impact individuals undergoing IVF who hope to generate the greatest number of oocytes for future retrieval.  

●Impact of endometrioma surgery (cystectomy) – Ovarian surgery to remove the endometrioma (ie, cystectomy) is associated with reduced ovarian reserve as assessed by AMH levels but not by antral follicle count (AFC) [34-37]. It is unclear if AMH falls because of surgical trauma to the ovary or removal of normal ovarian tissue and follicles.

•Cystectomy and AMH – A meta-analysis of 14 prospective studies comparing pre- and postoperative AMH and AFC levels in 650 females who underwent endometrioma resection (cystectomy) reported reductions in weighted mean AMH of 44, 35, and 54 percent at early (one to six week), intermediate (two to six months), and late (nine to eighteen months) postoperative time intervals, respectively [34]. By contrast, weighted mean AFC levels were similar pre- and postoperatively. Other studies have reported bilateral cystectomy for endometriomas may result in a greater reduction in AMH levels than unilateral ovarian cystectomy [35,38]. While AMH does not predict the probability of natural conception, it does predict the likelihood of live birth following IVF [34].

•Repeat surgeries and AMH – A prospective study that assessed ovarian function reported a greater loss of ovarian tissue and antral follicles in the females undergoing repeat surgery compared with those undergoing primary endometrioma resection [39]. The authors cautioned against repeat surgical intervention for endometriomas, particularly among patients desiring future pregnancy.

DISCUSS TREATMENT GOALS AND OPTIONS

●Goals – The goals of endometrioma treatment are to relieve symptoms (eg, pain or mass), exclude malignancy, and improve subfertility (if assisted reproductive technology is not being pursued), all while preserving ovarian function.  

●Treatment options – The main treatment options include: (1) active surveillance with serial imaging, (2) hormonal medical therapy for improvement of symptoms and reduction of cyst size, or (3) surgical treatment with cystectomy or oophorectomy. Selection of treatment approach is largely driven by patient preferences regarding desire for definitive therapy versus preference for preservation of ovarian reserve with less invasive, but ongoing, surveillance. Additionally, active surveillance can be combined with hormonal or nonhormonal medication. Further, the treatment approach may change over time depending on the patient's symptoms and preferences combined with the evolving characteristics of the cyst (ie, concern for malignancy). (See 'Baseline evaluation' above.)

ALARM FINDINGS OR DIAGNOSES — For patients with endometrioma, alarm diagnoses and findings include:

●Ovarian torsion from mass effect

●Cyst rupture with hemorrhage and/or hemodynamic instability

●Imaging results suggestive of malignancy

●Imaging changes over time that raise concern for malignancy (see 'Indications for change in management' below)

Patients with symptomatic cyst rupture or ovarian torsion require emergency surgery while those with findings concerning for malignancy receive expedited surgical evaluation and treatment. At the time of surgery, the decision for cystectomy with ovary preservation versus oophorectomy with removal of intact endometrioma is based on the risk of malignancy and clinical scenario. In general, patients with complications of endometrioma, such as cyst rupture and hemorrhage, undergo cystectomy, if possible, while those with concern for malignancy, such as postmenopausal patients, undergo oophorectomy. Surgical techniques and postoperative care are reviewed in detail below.

●(See 'Cystectomy with ovary conservation' below.)

●(See 'Oophorectomy (definitive surgery)' below.)

●(See 'Postoperative management' below.)

ASYMPTOMATIC ENDOMETRIOMA — Patients with an average risk of ovarian cancer who have asymptomatic endometriomas may elect active surveillance, with or without medical therapy, or surgical removal.

Active surveillance versus other options — For individuals with asymptomatic cysts that have the imaging-based characteristics of an endometrioma and no other clinical risk factors for ovarian cancer, we suggest active surveillance (ie, serial imaging) rather than surgical removal. Active surveillance is advised for most patients because it maintains ovarian reserve and avoids surgical risk. Active surveillance is particularly appropriate for patients with small lesions (≤5 cm) and those who prioritize preserving ovarian function [40]. However, patients with endometriomas may elect surgery for diagnosis and treatment after appropriate counseling. Surgical treatment is discussed below. (See 'Moderate-to-severe symptoms' below.)

Active surveillance can be combined with hormonal medical therapy for patients who desire medical treatment or who have mild symptoms (eg, pelvic pain and/or dysmenorrhea). Hormonal medical therapy is the same as for patients with symptomatic endometriomas. (See 'Mild symptoms' below.)

●Benefits – Active surveillance is generally advised because it is a minimally invasive approach (requires transvaginal ultrasound), preserves ovarian function [41-43], and avoids surgical risk. Observation over time also allows other benign ovarian cysts that could be confused for an endometrioma, such as hemorrhagic cysts, to regress.

●Disadvantages – The risks of observation include lack of histologic diagnosis, inability to exclude malignancy, and the need for serial imaging, typically with transvaginal ultrasound, with potential resultant stress.

●Contraindications – Patients with imaging findings concerning for malignancy, elevated baseline ovarian cancer risk, or moderate-to-severe symptoms are generally not candidates for active surveillance.

•(See 'Alarm findings or diagnoses' above.)

•(See 'Symptomatic endometrioma' below.)

•(See 'Unique patient populations' below.)

Surveillance process — Patients who elect active surveillance undergo serial evaluations to confirm findings consistent with an endometrioma and evaluate cyst stability (eg, size and features) over time. We assess symptoms, perform a physical examination, and repeat ultrasound imaging. A typical management plan involves physical examination and ultrasound every six months for one to two years, followed by annual examination and ultrasound if the adnexal mass has remained unchanged in size and clinical characteristics. Patients can be managed for many years using this conservative approach.

Indications for change in management — Onset of new symptoms, increasing cyst size (the authors use cyst diameter >5 cm), or increasing complexity on imaging (eg, cyst septations, nodules) should prompt closer follow-up. For these patients, the authors repeat pelvic ultrasound in 3 rather than 6 or 12 months. Two consecutive scans demonstrating clinically meaningful increased cyst volume or change in complexity of the cyst, or development of significant symptoms, should prompt surgical intervention. (See "Approach to the patient with an adnexal mass", section on 'When to stop surveillance or proceed with surgery'.)

SYMPTOMATIC ENDOMETRIOMA

Mild symptoms — For patients with mild endometrioma-related pain or mass symptoms, we suggest medical therapy rather than active surveillance or surgery. The rationale is medical therapies can improve quality of life, have established efficacy for endometriosis-related symptoms, and are generally low risk. Initial treatment options include hormonal medication, nonhormonal management of pain symptoms, or a combination thereof. Hormonal medical therapy may be particularly helpful for patients with dysmenorrhea and/or pelvic pain. Patients with mild symptoms who prefer active surveillance may reasonably do so. Surgical removal is an option for patients with large endometriomas (eg, size >5 cm); those whose symptoms do not improve, or worsen, with nonsurgical treatment; or those who desire cyst removal and have been adequately counseled. (See "Endometriosis: Treatment of pelvic pain".)

●Hormonal medical therapy – In contrast with earlier observational studies suggesting no effect [40,44,45], meta-analyses have reported hormonal medical therapy reduces endometrioma size and dysmenorrhea symptoms [46,47]. The benefits of nonsurgical management are balanced against the need for ongoing treatment, inability to exclude malignancy, and that hormonal treatment is not appropriate for, or accepted, by all patients. Medications associated with endometrioma reduction include dienogest, oral estrogen-progestin contraceptive pills, norethindrone plus letrozole, gonadotropin-releasing hormone (GnRH) agonists (eg, leuprolide acetate), relugolix, and danazol [46,47]. Drug selection is based on patient preferences around contraception use, side effects, and drug availability and cost. Detailed discussion of hormonal medication to treat endometriosis is available separately. (See "Endometriosis: Treatment of pelvic pain", section on 'Medical treatment options'.)

●Nonhormonal management of pain symptoms – Nonhormonal treatments, including nonsteroidal anti-inflammatory drugs (NSAIDs) and complementary therapies, are an option for patients who desire medical management but cannot use or decline hormonal medication, or whose symptoms do not adequately improve with hormonal medication alone. The approach is the same as treating pelvic endometriosis.

•(See "Endometriosis: Treatment of pelvic pain", section on 'Nonsteroidal anti-inflammatory drugs'.)

•(See "Endometriosis: Treatment of pelvic pain", section on 'Complementary therapies'.)

Moderate-to-severe symptoms — Patients with moderate-to-severe symptoms can elect a trial of medical management or proceed directly with surgery for diagnosis and treatment. Patients with significant symptoms (typically pain and/or mass effect), symptoms that interfere with routine activities and quality of life, or symptoms that do not adequately improve with medical management often desire surgical removal of the endometrioma [25,40]. However, patients who prefer to avoid surgery may reasonably do so if there are no alarm findings or concerns for malignancy. Options for active surveillance, with or without medical therapy, are then discussed. (See 'Surveillance process' above.)

●Surgical options and risks – Surgical options include cystectomy (ie, cyst removal with ovary conservation) or oophorectomy (ie, removal of ovary with endometrioma intact). Both surgical approaches allow definitive diagnosis, may reduce symptoms, and potentially improve subfertility . Surgery is typically performed by laparoscopy (image 2) with the goal of minimizing ovarian trauma. Risk includes decreased ovarian reserve in addition to standard surgical risks [41,48,49].

●Selection based on patient-important outcomes – For patients with a symptomatic endometrioma and/or an expanding suspected endometrioma, we suggest cystectomy for initial surgical treatment rather than oophorectomy. However, the decision for cystectomy or oophorectomy ultimately depends on the patient's preferences around continued ovarian hormone function, future fertility, and risk of endometrioma recurrence. Cystectomy preserves ovarian function but endometriomas may recur while oophorectomy prevents cyst recurrence but results in loss of that ovary's function, including all follicles. Patients with concerns for malignancy generally undergo oophorectomy.

UNIQUE PATIENT POPULATIONS

Infertility — Endometriosis and endometriomas are associated with infertility. For those with endometriomas, surgical excision may improve spontaneous pregnancy rates shortly after excision, but surgery has not been shown to improve the outcomes of advanced reproductive technologies such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). A decision for or against surgery should be based on a discussion with the patient and consideration of their values, goals, and plans for fertility treatment. (See "Endometriosis: Treatment of infertility in females".)

Increased baseline risk of ovarian cancer — People with somewhat elevated risk for ovarian cancer, but without known BRCA1 or BRCA2 mutations must be advised of the small but real incidence of the development of endometrioid or clear cell ovarian carcinoma within endometriomas. Risk increases with increasing age and size of the endometrioma. Patients' values and concerns should be considered in determining the appropriateness of definitive surgery to prevent ovarian cancer. The consequences of surgical menopause are balanced against the risks of continued observation of endometriomas. Cystectomy will not reduce the risk of ovarian cancer. The genetic risk associated with non-BRCA risk alleles, such as RAD51C and PALB2, generally permits delaying oophorectomy until after 40 years of age.  

Detailed discussion of ovarian cancer risk factors, including BRCA1 and BRCA2 mutations, and available testing options are available in related content.

●(See "Genetic testing and management of individuals at risk of hereditary breast and ovarian cancer syndromes".)

●(See "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Incidence and risk factors".)

●(See "Overview of hereditary breast and ovarian cancer syndromes".)

Recurrent endometrioma — Approximately 25 percent of patients who undergo surgical endometrioma removal will experience endometrioma recurrence [50-52]. In a study of 289 women who had undergone endometrioma resection, risk factors for endometrioma recurrence included removal of a cyst >8 cm, younger age (<25 years), and preoperative cyst rupture [50]. Postoperative approaches to reduce the risk of endometrioma recurrence are discussed below. (See 'Postoperative management' below.)

When recurrent endometrioma is suspected, repeat imaging is performed to reasonably exclude malignancy. Options for management then depend on the patient's symptoms, preferences for treatment, and risk of malignancy. (See "Approach to the patient with an adnexal mass", section on 'Patients at increased risk of malignancy'.)

●Asymptomatic – Asymptomatic recurrent endometriomas without imaging findings concerning for malignancy are generally managed with active surveillance in the same manner as initial endometriomas. Cysts with concerning findings warrant further evaluation.

●Symptomatic or concerning findings – Patients with recurrent endometriomas that are significantly symptomatic or have imaging findings suggestive of malignancy are offered oophorectomy. Oophorectomy is preferred for patients with recurrent disease who have completed childbearing but may be necessary for symptom control in patients who desire future fertility.

●Concerns for repeat cystectomy – For patients with recurrent endometriomas, we advise against repeat cystectomy and encourage active surveillance or medical therapy instead. The rationale is that repeat cystectomy may be more damaging to the ovary than initial cystectomy, although supporting data are limited to very small observational studies [39,53]. However, repeat cystectomy is reasonable for patients with significant symptoms who desire surgical treatment with ovary preservation (eg, patients attempting conception or undergoing IVF). Oophorectomy is an option for patients who desire definitive surgery. (See 'Oophorectomy (definitive surgery)' below.)    

•One study of 11 women undergoing endometrioma cystectomy reported that the cyst wall specimen was thicker and contained more normal ovarian tissue in the recurrent endometrioma group as compared with the primary endometrioma resection group [39]. The recurrent endometrioma resection group also had a reduced antral follicle count (AFC) and ovarian volume on follow-up ultrasound study.

•In another study that compared 18 women undergoing a second unilateral endometrioma resection with 18 women who underwent a primary resection only, the repeat resection group had decreased anti-müllerian hormone (AMH) levels, higher basal follicle-stimulating hormone (FSH) levels, and lower AFCs compared with the primary resection group [53]. Of note, the values for AMH, FSH, and AFC were not different between the groups after the primary surgery, which indicates the second surgery had an increased negative impact on ovarian reserve.

DESCRIPTION OF SURGICAL TECHNIQUES

Cystectomy with ovary conservation

Procedure — For patients with a symptomatic endometrioma and/or an expanding suspected endometrioma, we suggest cystectomy, preferably by the laparoscopic route (image 2), rather than oophorectomy . Cystectomy involves removal of the endometrioma cyst while leaving the remainder of the normal ovary intact (ie, preserves ovarian reserve and function) [18]. When cystectomy is elected, surgical resection or ablation are preferred to cyst drainage [54]. Other sites of endometriosis are treated at the same time. We inform patients that conversion to laparotomy occurs in approximately 5 percent of attempted laparoscopic cystectomies for endometriomas, which is higher compared with other benign ovarian lesions [55].

Surgical issues specific to endometrioma cystectomy include the method of cyst removal, choice of hemostatic agent, and the extent of adjacent disease. Additional discussion of ovarian cystectomy is presented in related content. (See "Oophorectomy and ovarian cystectomy" and "Oophorectomy and ovarian cystectomy", section on 'Cystectomy'.)

●Method of cyst removal – We incise the ovarian capsule to reach the cyst and strip the cyst wall from the ovary, rather than perform a circular excision around the cyst, to limit the number of normal ovarian follicles removed with the specimen [56]. A histologic analysis of endometriomas showed endometriosis of the inner cyst wall rarely penetrates more than 1.5 mm into the cyst capsule [57].

●Hemostatic technique – Choice of hemostatic technique used on the ovary appears to impact postoperative anti-müllerian hormone (AMH) levels [58-62]. Two different meta-analyses reported hemostatic sealants and suture caused less reduction in AMH levels compared with bipolar electrosurgery [63,64]. We agree with the study authors' suggestion to limit the use of bipolar electrocoagulation on the ovary. (See "Instruments and devices used in laparoscopic surgery", section on 'Electrosurgery'.)

●Adjacent disease and/or adhesions – In our experience, endometrioma removal is often more difficult than removal of other benign ovarian cysts because diffuse endometriosis may be present and there is likely to be dense scarring to structures adjacent to the cyst, making complete cystectomy more challenging. Thus, we discuss the potential need for oophorectomy with all individuals planning surgery. Any other endometriotic lesions are treated at the same time.

●Management of other benign cysts – Many patients with endometriomas also have other benign ovarian cysts, such as hemorrhagic corpus luteum cysts or follicular cysts. While these adjacent cysts often increase the difficulty of endometrioma removal, they are left in situ when possible in an effort to retain as much normal ovarian tissue as possible.

●Evaluation for malignancy – We perform pelvic washing and frozen section evaluation in cases with suspicious or unusual morphology, either by ultrasound or direct visualization at the time of surgery. Oophorectomy and appropriate staging is performed if the frozen section discloses malignancy.

Cystectomy versus aspiration, fenestration, or sclerotherapy — Cystectomy, preferably by laparoscopy, is preferred to other cyst treatments because it is associated with a lower risk of endometrioma recurrence [21,25].

●Aspiration – Cyst aspiration alone is ineffective with reported recurrence rates of 80 to 100 percent at six months of follow-up [65-68]. (See "Oophorectomy and ovarian cystectomy", section on 'Aspiration and fenestration versus cystectomy'.)

Cyst drainage with placement of oxidized regenerated cellulose (commercial name Surgicel) is a promising technique to preserve ovarian function with recurrence rates similar to cystectomy [69]. More data are needed before this approach becomes standard of care.

●Fenestration and ablation – Fenestration (removal of part of the cyst wall) and ablation (coagulation or laser vaporization of the inner side of the wall) is less effective than cystectomy, both in terms of improving fertility and reducing pain, but may have less impact on ovarian reserve [21,70]. (See "Oophorectomy and ovarian cystectomy", section on 'Aspiration and fenestration versus cystectomy'.)

●Cyst sclerotherapy – While cyst sclerotherapy has been attempted as a less invasive alternative to cystectomy, it is not advised because it has an unacceptably high recurrence rate, has variable impact on associated symptoms, and may reduce ovarian reserve as measured by AMH levels [71,72]. Endometrioma recurrence rates up to 63 percent have been reported, without an improvement in clinical pregnancy rate, when compared with traditional cystectomy or no treatment [71,72]. The effect of sclerotherapy on serum AMH levels is unclear as both unchanged and reduced AMH levels have been reported post-procedure, but reported reductions were smaller than those associated with surgical cystectomy [72,73]. In select patients, cyst sclerotherapy may be used to reduce cyst size if the only goal is improving access to follicles for aspiration during an in vitro fertilization (IVF) cycle [74].

Sclerotherapy consists of injecting a sclerosing agent (ethanol, tetracycline, or methotrexate) into the cyst cavity and is thought to disrupt the cyst epithelial lining, which results in inflammation, fibrosis, and, ultimately, obliteration of the cyst. The procedure can be performed laparoscopically or vaginally.

Oophorectomy (definitive surgery) — Oophorectomy involves removal of the ovary with the cyst intact and provides definitive surgical treatment. However, oophorectomy results in loss of ovarian function and bilateral oophorectomy in those under age 50 appears to increase the risks of all-cause mortality and cardiovascular disease. Decision to remove an ovary involves careful discussion on the risks of endometrioma recurrence and symptoms compared with risks and sequelae of loss of ovarian hormones and follicles. (See "Elective oophorectomy or ovarian conservation at the time of hysterectomy", section on 'Consequences of elective oophorectomy'.)

●Indications – Oophorectomy is mainly performed in patients who have recurrent cysts, have completed childbearing, are postmenopausal, or who have concerns for malignancy [18]. Unilateral oophorectomy resolves symptoms and reduces the risk of endometrioma recurrence. However, endometriomas or other cysts can still form in the contralateral ovary and, rarely, a retained ovarian remnant can cause pain symptoms. (See "Oophorectomy and ovarian cystectomy", section on 'Ovarian remnant syndrome'.)

●Impact on ovarian hormone production

•Unilateral oophorectomy – The impact of unilateral oophorectomy on ovarian hormone production is unclear. Most studies that assess hormone production from the remaining ovary have looked at patients undergoing hysterectomy with and without unilateral oophorectomy. In studies of women having hysterectomy, the time interval to cessation of ovarian function is shorter for those who have unilateral oophorectomy in addition to hysterectomy, which raises concern that oophorectomy alone may reduce residual ovarian function [75-78]. Premature loss of ovarian function is associated with increased risk for cognitive impairment and cardiovascular events [78-80]. (See "Elective oophorectomy or ovarian conservation at the time of hysterectomy", section on 'Consequences of elective oophorectomy'.)

•Bilateral oophorectomy – Bilateral oophorectomy results in complete loss of ovarian function. Thus, this procedure is typically reserved for patients who have debilitating symptoms, have had inadequate response to other therapies, and have completed childbearing [40]. Bilateral oophorectomy can be performed with or without concomitant hysterectomy and/or bilateral salpingectomy. (See 'Concomitant surgery' below.)

●Removal of entire adnexa (en bloc dissection) – If the patient has extensive unilateral pain and/or scarring around the ovary containing the endometrioma, the patient may benefit from removal of the entire adnexa (ie, en bloc dissection of the ovary, fallopian tube, and surrounding tissue). This dissection may necessitate opening the retroperitoneum, identifying and isolating the ureter, and ligating the infundibulopelvic ligament near the pelvic brim to avoid operating near the diseased tissue. This approach reduces the risk of retained ovarian tissue that could cause further symptoms. (See "Ovarian remnant syndrome".)

Concomitant surgery

Hysterectomy — Patients with severe endometriosis and/or endometriosis-related symptoms who have completed childbearing may elect removal of the uterus to reduce pain symptoms. Hysterectomy can be performed with either cystectomy (for maintenance of some ovarian function) or oophorectomy. Total hysterectomy with bilateral oophorectomy is considered definitive surgery and generally limited to patients who have had inadequate response to other treatments and completed childbearing, if desired. (See "Endometriosis: Surgical management of pelvic pain", section on 'Hysterectomy'.)

Prophylactic salpingectomy — Individuals who elect surgery with either ovarian cystectomy or oophorectomy have the option of concurrent salpingectomy (removal of the fallopian tubes) to reduce the risk of epithelial ovarian, fallopian tube, and peritoneal cancers. The balance of risks and benefits for this additional surgery depend on the patient's baseline risk of these cancers. Salpingectomy for cancer risk reduction is presented in detail in related content.

●(See "Risk-reducing salpingo-oophorectomy in patients at high risk of epithelial ovarian and fallopian tube cancer".)

●(See "Opportunistic salpingectomy for ovarian, fallopian tube, and peritoneal carcinoma risk reduction".)

POSTOPERATIVE MANAGEMENT

Goals of treatment — The use of postoperative medical therapy depends on the indication(s) for surgery and the patient's preferences regarding immediate attempt at pregnancy, use of medication, potential side effects of medication, and risk of cyst recurrence.

●Reduction of endometriosis-related pain recurrence – For premenopausal individuals who undergo surgical resection of endometrioma and are not planning immediate pregnancy, we suggest postoperative use of suppressive medical therapy rather than observation. Postoperative medical suppressive therapy reduces disease recurrence and dysmenorrhea, thus avoiding need for multiple surgeries, and is of low risk [18,25,40,81]. Options include estrogen-progestin contraceptives, progestin-only therapies, gonadotropin-releasing hormone (GnRH) agonists and antagonists, and levonorgestrel intrauterine devices (LNG IUDs). Selection is based on patient preferences around contraception, dosing, and side effects. Estrogen-progestin contraceptive pills are often used because of general tolerability, availability, and ease of use in addition to data supporting reduced endometrioma recurrence rates with long-term (one year or greater) use [82,83]. (See "Endometriosis: Treatment of pelvic pain", section on 'Medical treatment options'.)

Individuals who desire immediate attempt of pregnancy are an exception. Discussion of treatment options and supporting data are reviewed separately. (See "Endometriosis: Surgical management of pelvic pain", section on 'Postoperative care'.)

●Reduction of endometrioma recurrence – Postoperative medical treatment appears to reduce the risk of endometrioma recurrence if maintained for at least a year [82,84,85]. The optimal drug regimen is not known and the available data are mixed. Although the supporting data are of low quality, long-term suppression with combined estrogen-progestin contraceptives appears to be helpful and is of low overall risk. (See "Endometriosis: Treatment of pelvic pain", section on 'Estrogen-progestin contraceptives'.)

•A 2022 network meta-analysis comparing multiple medical treatments with expectant management reported combined therapy with a GnRH agonist and dienogest was associated with lower risk of endometrioma recurrence compared with GnRH agonist alone or expectant management (mean treatment duration of at least 12 months) [82]. Hormonal suppression included oral contraceptive (OC) pills (multiple formulations), dienogest, and LNG IUDs. The risk of endometrioma recurrence was similar for treatment with GnRH agonist alone and expectant management (odds ratio 0.47, 95% CI 0.12-1.89). Shorter duration of treatment (three to six months) was not associated with reduced recurrence risk.

•A 2021 network meta-analysis of six trials and 16 cohort studies reported a nonsignificant trend toward lower endometrioma recurrence rates with postoperative use of hormonal suppression, including OCs (continuous and cyclic), dienogest, LNG IUDs, and GnRH agonist therapy, compared with expectant management [84].

Options

●Oral contraceptives (OCs) – Postoperative treatment with either a cyclic or continuous estrogen-progestin OC regimen is reasonable as treatment has been associated with reduced risk of endometrioma recurrence and reduction of endometriosis-related symptoms [82,83,85-87]. Continuous-dose OC regimens may provide additional benefit over cyclic ones [88]. Combined therapy with estrogen and progestin is preferred to progestin treatment alone; a study of endometrioma cells reported that cell growth was suppressed more by combination therapy with ethinyl estradiol and progestin than by progestins alone as a result of the up-regulation of progesterone beta receptors by the 17 beta-ethinyl estradiol [89]. Estrogen-progestin contraceptive vaginal rings and patches have also been associated with reduction in endometriosis-related symptoms, but their impact on postoperative endometrioma recurrence has not been established [90].

•(See "Endometriosis: Surgical management of pelvic pain", section on 'Postoperative medical therapy'.)

•(See "Endometriosis: Treatment of pelvic pain", section on 'Estrogen-progestin contraceptives'.)

●Dienogest – Studies have reported postoperative dienogest reduced risk of endometrioma recurrence, was associated with resolution of recurrent cysts, and preserved anti-müllerian hormone (AMH) levels [91-93]. If available, it may be as part of a combined estrogen-progestin contraceptive pill containing either ethinyl valerate or ethinyl estradiol (table 2). If used, treatment of six months or greater is advised as shorter duration of treatment has been associated with endometrioma recurrence risk similar to that of expectant management [84].

●GnRH agonists and antagonists – Both gonadotropin-releasing hormone (GnRH) agonist and antagonist therapy can be used for postoperative suppressive therapy for endometriosis and its related symptoms [94-97]; impact on endometrioma recurrence is less clear [84]. (See "Endometriosis: Treatment of pelvic pain", section on 'Gonadotropin-releasing hormone (GnRH) analogs'.)

●Levonorgestrel intrauterine devices (LNG IUDs) – While studies report reduced rates of dysmenorrhea in patients treated with LNG IUDs after surgical removal of endometriomas, the impact of LNG IUDs on endometrioma recurrence is less clear because of small study size, short duration of follow-up, and lack of placebo comparator [98-100]. Until further data are available from larger trials, we do not advise LNG IUD insertion for prevention of endometrioma recurrence and instead offer patients treatment with OCs as described in the first bullet. (See "Endometriosis: Treatment of pelvic pain", section on 'Alternate progestin treatment options'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Endometriosis".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●The Basics topic (See "Patient education: Endometriosis (The Basics)".)

●Beyond the Basics topic (see "Patient education: Endometriosis (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Baseline evaluation – The baseline evaluation for individuals with suspected endometriomas includes assessment of symptoms; physical examination; imaging, typically with transvaginal pelvic ultrasound; evaluation of malignancy risk; and consideration of the patient's plans for future fertility. (See 'Baseline evaluation' above.)

●Importance of ovarian reserve – Endometriomas themselves do not appear to diminish ovarian reserve but surgery to remove them is associated with reduced anti-müllerian hormone (AMH) levels. While AMH level does not predict the probability of natural conception, it does predict live birth following in vitro fertilization (IVF). (See 'Consider importance of ovarian reserve' above.)

●Treatment options – The main treatment options include active surveillance with serial imaging, hormonal medical therapy to treat pain/dysmenorrhea and possibly reduce cyst size, or surgical removal, either by cystectomy or oophorectomy. (See 'Discuss treatment goals and options' above.)

●Treatment selection – The approach to management is determined by cyst characteristics on imaging and the patient's presentation, symptoms, baseline risk factors for ovarian cancer, and preferences.

•Alarm diagnoses or findings – Alarm diagnoses include ovarian torsion and cyst rupture with hemodynamic instability; alarm findings include imaging results suggestive of malignancy. Patients with ovarian torsion or complicated cyst rupture require emergency surgery, while those with concerns for malignancy receive expedited surgical treatment. At the time of surgery, the decision for cystectomy with ovary preservation, versus oophorectomy with removal of intact endometrioma, is based on the clinical scenario and risk of malignancy. (See 'Alarm findings or diagnoses' above.)

•Asymptomatic endometrioma – For individuals with asymptomatic cysts that have the imaging-based characteristics of an endometrioma and no other clinical risk factors for ovarian cancer, we suggest active surveillance (ie, serial imaging) rather than surgical removal (Grade 2C). Active surveillance maintains the patient's ovarian reserve and avoids surgical risk. However, patients who desire definitive surgical diagnosis, and/or decline repeated imaging, and understand the potential negative impact of surgery on ovarian function may reasonably elect surgical excision. (See 'Asymptomatic endometrioma' above.)

•Mild symptoms – For patients with mild endometrioma-related pain or mass symptoms, we suggest medical therapy rather than active surveillance or surgery (Grade 2C). Medical treatment, either hormonal or nonhormonal, can improve quality of life, may reduce the cyst size, and is generally low risk. Patients with mild symptoms who prefer active surveillance may reasonably do so. Surgical removal is an option for patients with large endometriomas (eg, size >5 cm), those whose symptoms do not adequately improve (or worsen), or those who desire cyst removal and have been adequately counseled. (See 'Mild symptoms' above.)

•Moderate-to-severe symptoms – Patients with significant endometrioma-related symptoms (eg, pain, mass effect) are offered medical management or surgical removal of the endometrioma. For patients who desire surgical management and have typical imaging findings of endometrioma, we suggest cystectomy for initial surgical treatment rather than oophorectomy (Grade 2C). While both procedures remove the endometrioma, cystectomy preserves ovarian function and follicles. However, the decision for cystectomy or oophorectomy ultimately depends on the patient's preferences around continued ovarian hormone production, future fertility, and tolerance for of endometrioma recurrence. (See 'Moderate-to-severe symptoms' above.)

•Unique populations – Patients with infertility, an elevated baseline risk of ovarian cancer, and/or recurrent endometrioma (with or without symptoms) require additional consideration. Approximately 25 percent of women who undergo surgical endometrioma removal will experience endometrioma recurrence. Repeat cystectomy to remove a recurrent endometrioma may be more damaging to the ovary than initial cystectomy. (See 'Unique patient populations' above.)

●Surgical techniques and selection

•Cystectomy – For patients who elect surgery with ovary conservation, we recommend cystectomy rather than other procedures (eg, cyst aspiration, cyst fenestration and ablation, or sclerotherapy) (Grade 1B). Compared with cystectomy, other procedures are associated with significant risks of cyst recurrence (recurrence risk of 25 percent versus 60 to 80 percent). Fenestration and ablation are less effective than cystectomy in reducing pain and improving fertility. We perform laparoscopic cystectomy with the stripping technique to preserve normal ovarian tissue. (See 'Cystectomy with ovary conservation' above.)

•Oophorectomy – Oophorectomy involves removal of the ovary with the cyst intact and provides definitive surgical treatment. Bilateral oophorectomy, with or without concomitant hysterectomy, is reserved for individuals who have debilitating symptoms, have inadequate response to other therapies, and/or have completed childbearing. (See 'Oophorectomy (definitive surgery)' above.)

●Postoperative treatment – For premenopausal individuals who undergo surgical resection of endometrioma and are not planning immediate pregnancy, we suggest postoperative use of suppressive medical therapy rather than observation (Grade 2B). Postoperative medical suppressive therapy reduces disease recurrence and dysmenorrhea, thus avoiding need for multiple surgeries, and is of low risk. (See 'Postoperative management' above.)