Last updated date: 20-Apr-2023

Originally Written in English




Endometriomas are cysts that grow on the ovaries and are sometimes known as "chocolate cysts" due to their dark hue. Endometrial tissue that forms on the ovaries causes these cysts. Endometrioma can develop in women with endometriosis.

Endometrioma symptoms include painful periods and profuse menstrual flow. Expectant management, medicinal and/or surgical therapy, and in vitro fertilization are all alternatives for treatment. The choice of therapy is primarily determined by the related symptoms.


Ovarian endometrioma

Ovarian endometrioma

Endometriomas are cystic lesions caused by the endometriosis disease process. Ovarian endometrioma is a benign, estrogen-dependent cyst that occurs in reproductive-age women. Ovarian endometriomas are linked to infertility; while the specific cause is uncertain, oocyte number and quality are considered to be impaired.

The ovaries are the most prevalent location for endometriomas. Endometriosis, which affects around 10% of reproductive-aged women, is a prevalent cause of persistent pain, dyspareunia, dysmenorrhea, and infertility. Endometriosis is most typically located in the pelvic, specifically on the ovaries. Endometriomas are the most prevalent ovarian endometriosis manifestation.

Because of the thick dark brown look of the fluid contained within these tumors, they are usually referred to as chocolate cysts. Endometriomas signify a more severe disease state in endometriosis patients and can cause unique problems in these individuals, such as diminished ovarian reserve. 



Endometriosis has been shown to afflict roughly 10% of women of reproductive age. However, clinically severe illness affects only approximately 3% of reproductive-aged women. There are distinct populations among this 3% that have a high prevalence of endometriosis. Endometriosis, for example, has been discovered in almost 50% of women suffering infertility troubles and nearly 70% of women experiencing pelvic discomfort.

When it comes to the prevalence of endometriomas, there is a scarcity of data. However, it is expected that 17-44 percent of women with endometriosis will develop an endometrioma, with 28 percent developing bilateral endometriomas. Endometriomas are seen in roughly 17% of the women in the subfertility population.

There is also a scarcity of evidence to establish distinct risk factors for endometriomas on their own. However, there are established risk factors for endometriosis development in general.

These include:

  • Nulliparity
  • Early menarche (typically before 11-13 years old) 
  • Late menopause, short menstrual cycles (less than 27 days) 
  • Heavy menstrual bleeding
  • Mullerian anomalies
  • Height greater than 68 inches
  • Low body mass index (BMI) 
  • Consumption of high amounts of trans unsaturated fat
  • Exposure to diethylstilbestrol in utero

In addition to endometriosis risk factors, there are several things that endometriosis puts the patient at a higher risk for. Many of them have already been covered, including infertility, persistent pelvic discomfort, dyschezia, dyspareunia, and dysmenorrhea. Endometriosis, on the other hand, has been linked to an elevated risk of certain kinds of ovarian cancer in women.

Ovarian cancer remains a low-risk disease in general. Several studies, however, have found that women with endometriosis had an increased risk of developing clear cell and endometrioid ovarian cancer. One research in particular from Finland discovered this elevated risk solely in women with endometriomas.



Endometriomas are hypothesized to be generated when ectopic endometrial tissue, which is most typically seen on the ovary, bleeds and forms a hematoma. Because the ectopic endometrial tissue is still hormonally active, this usually occurs throughout a woman's regular menstrual cycle. As a result, this tissue will shed spontaneously with the withdrawal of progesterone following the dissolution of the corpus luteum.

However, unlike typical hematomas observed after ovulation, they are coated with sticky endometrial stroma and glands and contain more fibrous tissue. As a result, they are more usually found with adhesions present to adjacent tissues, which can cause substantial pain for the patient as well as a variety of complications for the surgeon during surgical removal of an endometrioma. 

When examining the etiology of endometriomas, it is usually appropriate to also explore the etiology of endometriosis, as this is the precursor condition to an endometrioma. The genesis of endometriosis, on the other hand, is a contentious topic in the medical profession. Retrograde menstruation is the earliest and most commonly recognized hypothesis for the genesis of endometriosis.

According to this idea, endometriosis develops as a result of endometrial tissue moving retrogradely via the fallopian tubes and into the pelvis during a woman's normal menstrual cycle. This tissue subsequently spreads and seeds throughout the body, resulting in endometriosis lesions. As previously described, some of these lesions may seed to an ovary and start the process of becoming an endometrioma.

This retrograde menstruation notion is most likely a role in the development of endometriosis. However, most medical professionals believe that it is a multifactorial development. This notion, for example, is difficult to accept in women with distant endometriosis lesions or in pre-pubescent females with endometriosis.

As a result, additional hypotheses have been proposed, such as the notion of metaplasia. According to this view, extrauterine cells undergo metaplasia and transdifferentiate into endometrial cells. Another widely held belief is that viable endometrial cells are implanted by hematogenous and lymphatic dissemination. There is no single idea that has been thoroughly confirmed, and it is most likely a blend of the hypotheses described above.



Pathophysiology of Endometrioma

Endometriomas have the same pathophysiology as endometriosis in general since they are a subgroup of this bigger medical disorder. The hormonal reaction of the ectopic endometrial tissue initiates the illness process. This tissue, like the intrauterine endometrium, reacts to the periodic hormonal changes of a woman's menstrual cycle.

It will proliferate, secrete, and slough just like it would if it were in the uterus. Variations in cytokine and prostaglandin concentrations result from these changes.

Cytokines and prostaglandins are signaling chemicals that initiate an inflammatory response, causing inflammation in the region of endometriotic implantation. This inflammatory reaction subsequently provides the groundwork for the creation of new vascularization and fibrous tissue. The adhesions and discomfort that are usually linked with this disease process are the result of this snowball effect.

These abnormalities also contribute to the disease's primary consequences, such as infertility and persistent pelvic discomfort. Endometrioma patients have a more severe disease condition and so often experience this on a larger scale than individuals with stage one or two endometriosis.


Endometrioma symptoms

Endometrioma symptoms


Patients with symptomatic endometriosis are often nulliparous females of reproductive age with a primary complaint of heavy or painful menstruation. Their periods are frequently longer than seven days. They may complain of persistent pelvic discomfort, pain during sexual intercourse, or pain during defecation. Their menstrual cycles are usually regular, however they may have shorter menstrual cycles (less than 27 days). The commencement of discomfort for these individuals is usually 2-3 days before the starting of their menstruation, and the pain usually begins to resolve a couple of days after their menstruation has begun.

Endometriomas may be excruciatingly painful. They are most often located on the ovaries, and the discomfort is usually localized to one side of the lesion. Patients may have bilateral or widespread pain depending on the amount of their illness and the laterality of their lesions. When an ovarian endometrioma ruptures, thick endometrial fluid can spread into the belly, causing severe discomfort and inflammation. These individuals frequently appear with a surgical abdomen that is inflamed.

Although endometriomas are more typically identified in the ovaries, it is critical to be cautious with patients who present with pain symptoms. Endometriomas have been discovered in unexpected areas. Endometriomas, for example, have been found in several recorded cases within abdominal surgical incision scars.

 Endometrial implants have been found in the lung parenchyma and the brain. Endometriosis should be considered whenever a patient complains of pain that is cyclical in nature with their menstrual cycles, regardless of where the discomfort is located.



  • Pelvic pain
  • Heavy menses
  • Painful menses
  • Back pain
  • Painful sexual intercourse (dyspareunia)
  • Painful defecation (dyschezia)
  • Painful urination (dysuria)
  • Urinary frequency
  • Nausea/vomiting
  • Bloating



Physical examination results for endometriosis, including endometriomas, are often minor. Endometriomas can be felt on a bimanual exam if they are large enough. Aside from that, these individuals have just a few aberrant results. Soreness to the afflicted location or widespread pelvic tenderness is common. However, this might be affected by the time of the test in relation to the patient's menstrual cycle.

The patient will frequently experience more discomfort if the exam is performed right before the commencement of her menstruation as opposed to after her menstruation has ended. A fixed or retroverted uterus, indicating scarring owing to endometriosis, is another potential result on the bimanual exam. Nodularity of the uterosacral ligaments can also be palpated at times.

However, if a patient arrives after an endometrioma ruptures, the patient may have an acute abdomen upon assessment. Peritoneal symptoms, which usually manifest as abdominal stiffness, rebound pain, and involuntary guarding, are among these findings.



Diagnosis of Endometrioma

Endometriomas are frequently seen on imaging. On imaging, they seem identical to other cystic lesions, and the ultimate pathology is only revealed during surgery. If these features are not visible on imaging, the diagnosis becomes considerably more difficult. It is critical to note that surgical visibility of the lesions is required for a definite diagnosis of endometriosis. As a result, there is no diagnostic test that can be performed. There are, however, a limited number of tests that may be utilized to aid in the diagnosis.

A complete blood count (CBC), cancer antigen (CA)-125, CCR1, urinalysis, and sexually transmitted infection (STI) tests are all options for these patients. The CBC can aid in determining whether or not there is an infection or anemia. If the white blood cell count is increased, the doctor will be more likely to suspect an infectious cause of the patient's pelvic discomfort. Because these individuals often have larger periods and may be anemic as a result, hemoglobin can also assist lead you to the degree of blood loss.

CA-125 levels in endometriosis patients might be high. However, because this is a non-specific identifier, it is not commonly ranked. CCR1 is a novel lab marker that has been found to be greater in endometriosis patients' peripheral blood leukocytes. This is not currently a conventional practice, but it might be a test to explore in these individuals as part of their work-up.

It is also necessary to perform urinalysis to rule out a urinary tract infection from the differential diagnosis, as well as STD tests such as cervical cultures for gonorrhea and chlamydia.

When it comes to imaging, these patients are frequently given a transvaginal ultrasound to see whether there is a visible explanation for their pelvic pain. Endometriosis superficial implants cannot be visible on ultrasonography or any other imaging technique. Endometriomas, on the other hand, are frequently discovered using ultrasonography. Endometriomas usually manifest as simple cysts.

They can, however, be observed as multi-loculated cysts or cystic-solid lesions. The characteristic ultrasound appearance of these lesions is low-level homogeneous echos, often known as ground-glass look. This is compatible with the presence of ancient hemorrhagic debris. When studied with a doppler flow, these lesions are often devoid of vascularity.

Magnetic resonance imaging (MRI) and computed tomography are two further imaging modalities to consider (CT). MRI has been proven to be more sensitive than ultrasonography in identifying a pelvic mass. However, because an MRI is expensive, the benefit does not justify the financial burden, hence ultrasonography is more usually employed.

MRI, like ultrasonography, is restricted in identifying widespread pelvic endometriosis and may only be useful in detecting endometriomas. Although a CT scan exposes the patient to radiation, the features of the mass on the CT scan offer strong indicators as to the sort of mass it is. As a result, a CT scan is not the best imaging modality for these individuals.

Laparoscopy is the gold standard for diagnosing endometriosis. Because imaging and laboratory investigations are ineffective in diagnosing endometriosis, direct visualization through surgery is the gold standard. Endometriosis lesions are often blue or black in hue during laparoscopy. They can, however, appear as red, white, or non-pigmented lesions.

The severity of the illness can also be determined at this time. If there are substantial adhesions, peritoneal abnormalities, or endometriomas, it indicates a more serious illness. The visible lesions can then be biopsied and pathology examined for endometrial glands and stroma. If the patient is also having reproductive problems, chromotubation can be performed at this time to check tubal patency.

Laparoscopy is a significant technique in endometriosis patients because, in addition to being diagnostic, it is also therapeutic, especially in cases of endometriomas. This is a critical component of therapy for individuals with resistant endometriosis or symptomatic endometriomas.


Endometrioma treatment

Endometrioma treatment

Endometriosis therapy mostly comprises of hormonal drugs or surgical surgery. Milder cases of endometriosis can be treated with oral contraceptives, different kinds of progesterone (oral pill, intrauterine device), gonadotropin-releasing hormone (GnRH) agonists (such as leuprolide), or androgens (such as danazol)

However, if a patient's endometriosis has progressed to the appearance of an endometrioma, surgical treatment is usually preferable. Endometriomas can be reduced in size by using GnRH agonists. Patients, on the other hand, have noticed no difference in their discomfort. As a result, individuals with endometriomas are usually advised to forego this alternative.

Endometriosis surgical therapy can range from conservative to aggressive, depending on the patient's symptoms and desire for future fertility. Conservative surgery include removing endometrial lesions (usually with a laser or cautery), draining the endometrioma, and removing the cystic capsule. However, if a patient's discomfort is severe and she does not want to have children in the future, she may have complete hysterectomy with bilateral salpingo-oophorectomy as a more permanent solution.

Surgeries, particularly more conservative ones, are frequently performed laparoscopically. It is critical to remove the cyst wall during surgical excision of an endometrioma rather than merely emptying the cyst. It has been demonstrated that this reduces recurrence rates. Resection of an endometrioma has been demonstrated to enhance natural pregnancy chances in patients who are suffering reproductive issues.

The biggest concern with surgical endometrioma excision, particularly in women experiencing infertility and considering IVF, is if it impacts the quantity of ovarian reserve. Women with cystectomy had reduced AMH (anti-mullerian hormone) levels, which is a hormone used by fertility doctors to assess ovarian reserve. Ovarian failure has also been recorded in 2-3% of individuals following bilateral endometrioma excision.

As a result, these are essential hazards to consider when determining whether surgery is suitable for each patient based on their reproductive goals. Because of the scarcity of evidence, endometriomas are usually treated expectantly if patients are already seeing a reproductive expert and considering IVF. The only exception is if the endometrioma is causing significant symptoms or problems with egg retrieval.

Some physicians put patients on medicinal treatment after surgery to try to avoid a recurrence. A 6-month course of oral contraceptive tablets has been shown in trials to help prevent a recurrence. This treatment option, however, is dependent on the patient and whether or not they are attempting to conceive.


Differential Diagnosis

When examining individuals with suspected endometriomas, it is critical to investigate all probable diseases. Because of the confusing nature of endometriomas and endometriosis in general, it might appear similarly to other disorders.

Frequently, these individuals come with confused pelvic discomfort. Other causes of pelvic discomfort are also crucial issues to bear in mind. Among these are:

  • Ectopic pregnancy
  • Appendicitis
  • Pelvic inflammatory disease
  • Ovarian torsion
  • Diverticulitis
  • Urinary tract infection
  • An ovarian cyst (other than endometrioma)
  • Sexually transmitted infections (gonorrhea, chlamydia)


If an adnexal mass is present and identifiable by imaging, there are features of the mass that can help determine what type of adnexal mass it is. Endometriomas exhibit a typical ground glass look on ultrasonography, as detailed in the examination section above.

These characteristics are also observed in hemorrhagic cysts, and the distinction between the two is sometimes not realized until surgery. As a result, when dealing with imaging evidence of endometriomas, hemorrhagic cysts should be included in the differential diagnosis.

In addition, when a patient presents with an acute abdomen and there is worry for a ruptured endometrioma, the most critical things to consider are ruptured ectopic pregnancy and ovarian torsion. These are all surgical emergencies that must be treated as quickly as feasible in the operating room.



Patients with endometriosis have a good overall prognosis. This is a harmless sickness. However, it is a chronic illness that might worsen with time. Patients with endometriomas have more severe illness and may experience more long-term consequences as a result. Even if therapy is beneficial for a period of time, the illness is sadly prone to recurrence.

As a result, the biggest concern with this condition is the absence of genuinely definitive therapy, which can result in long-term complications such as discomfort and infertility. Fortunately, most women's symptoms improve as they reach menopause due to the lack of cyclical hormonal signaling.



Endometriomas have the same two primary problems as endometriosis in general. As previously stated in this article, these problems include persistent pelvic discomfort and infertility. Furthermore, if the endometrioma is 6 cm or larger, the patient is at a higher risk for ovarian torsion, which is a surgical emergency that can result in ovary loss. Endometriosis increases the risk of some forms of ovarian cancer, and endometriomas have a tiny chance of progressing to malignancy, albeit this is extremely unlikely.



Endometriosis is a non-cancerous, estrogen-dependent gynecological illness characterized by endometrial tissue outside the uterus. When caring for patients with endometriomas, it is critical to communicate treatment expectations as well as the potential problems of endometriosis.

Laparoscopic surgery is used to treat endometriomas. As a result, prior to undertaking a laparoscopic cystectomy, the patient should be educated on the risks and advantages of laparoscopic surgery. It is also critical for the patient to realize that endometriomas grow as a result of endometriosis, which is a persistent illness.

The patient should be informed that around 25% of women will have an endometrioma recurrence. Aside from recurrence, the patient may also face reproductive troubles and persistent pelvic discomfort as a result of their underlying endometriosis, which may necessitate further therapy.