Right ovarian cyst in women: causes, symptoms, and treatment options

An ovarian cyst is a fluid-filled cavity within the tissue or on the surface of an ovary. In women of reproductive age, most cysts are functional (follicular or corpus luteum cysts) and resolve spontaneously within 2-3 menstrual cycles. However, some lesions are pathological (endometrioma, dermoid cyst, cystadenoma) and require observation or surgery. The clinical goal is not to "scare" the patient, but to correctly distinguish harmless findings from those requiring active intervention. [1]

Localization to the "right" is important for differential diagnosis with appendicitis and because torsion of the appendages most often occurs on the right: this is facilitated by anatomy (the sigmoid colon on the left "fastens" the left ovary, while on the right there is more space and a longer ligament). Therefore, acute right-sided pain requires particularly careful examination and rapid visualization. [2]

Modern approaches rely on high-quality ultrasound examination using the IOTA lexicon and the O-RADS system (version 2022), which provide standard descriptions and recommend strategies based on the ultrasound phenotype. This reduces unnecessary surgeries and increases the detection of rare malignancies, especially in peri- and postmenopausal women. [3]

Treatment is chosen individually: observation with ultrasound monitoring, medication to manage symptoms, laparoscopic removal (cystectomy), or organ-preserving surgery in case of complications. The team (gynecologist, radiologist, and, if necessary, oncologist) discusses the risks, pregnancy plans, and the patient's preferences; most uncomplicated cysts can also be observed during pregnancy. [4]

Code according to ICD-10 and ICD-11

In ICD-10, ovarian cysts are classified under "N83 - Non-inflammatory diseases of the ovary, fallopian tube, and broad ligament." The most commonly used codes are: N83.0 "Follicular ovarian cyst," N83.1 "Corpus luteum cyst," and N83.2 "Other and unspecified ovarian cysts." Subcategories are used to specify the side: for example, N83.01 - "Follicular cyst of right ovary"; N83.201 - "Unspecified cyst of right ovary." This is useful for statistics, routing, and reporting. [5]

In ICD-11, ovarian cysts are classified under the "GA18 - Acquired ovarian anomalies" block: GA18.0 "Follicular ovarian cyst," GA18.6 "Other or unspecified ovarian cysts." ICD-11 supports post-coordination—modifiers for the side and clinical features can be added to the main code, facilitating analytical accounting. [6]

Table 1. Examples of correct coding

System	Code	Name	Example of a situation
ICD-10	N83.01	Follicular cyst of the right ovary	A simple thin-walled cyst measuring 35 mm on the right in a 28-year-old woman
ICD-10	N83.201	Unspecified cyst of the right ovary	Simple cyst 55 mm, type not determined on initial ultrasound
ICD-10	N83.1	Corpus luteum cyst	Thick-walled "ring" cyst 30 mm with hemorrhage
ICD-11	GA18.0	Follicular cyst of the ovary	Follicular cyst (with postcoordination "right")
ICD-11	GA18.6	Other or unspecified ovarian cysts	Unclear visual picture, follow-up ultrasound is expected [7]

Epidemiology

Simple cysts are a common finding. According to the SRU consensus, simple cysts are detected in up to 14% of postmenopausal women during initial ultrasound examinations, and even more frequently in premenopausal women, as most of them are physiological follicles and corpus luteum cysts. Some cysts appear and disappear within a single cycle without causing symptoms. [8]

In the general population, the proportion of women who have ever been diagnosed with cysts, according to various studies, ranges from 7% to 16%, and is higher in perimenopause. Although this is a common finding, the likelihood of malignancy in premenopausal women with symptomatic cysts is low - approximately 0.1-0.3% (1 in 1,000 to 3 in 1,000 by age 50). [9]

Acute complications are rare but clinically significant. Adnexal torsion occurs in approximately 5-10 cases per 100,000 women per year, more frequently during reproductive age and more often on the right; in children/adolescents, the incidence is approximately 4.9 per 100,000. These figures are important to understand: sharp, unilateral pain cannot be ignored. [10]

During pregnancy, up to 70% of adnexal lesions regress spontaneously, while a minority require surgery due to symptoms, growth, or suspicion of malignancy; laparoscopy in the second trimester is preferred when strictly indicated. [11]

Table 2. Epidemiology (key figures)

Indicator	Grade
Simple cyst in postmenopause (initial ultrasound)	≈14%
Cancer risk in symptomatic cysts in premenopausal women	≈0.1-0.3%
Torsion of appendages (in general)	≈5.9 per 100,000/year
Torsion in 1-20 years	≈4.9 per 100,000/year
Regression of adnexal formations during pregnancy	≈70% of cases [12]

Reasons

Functional cysts form during normal cycle phases: follicular cysts form during "failed" ovulation and fluid accumulation, and corpus luteum cysts form during hemorrhage/secretory changes after ovulation. These formations are not tumors, are usually small (up to 50 mm), and regress. [13]

Pathological cysts arise from ovarian tissue (endometrioma, dermoid cyst/mature teratoma, serous/mucinous cystadenoma) or adnexal tissue (parovarian cyst). Their walls are composed of a different tissue type, they are more often persistent, and sometimes grow. These cysts require risk stratification based on ultrasound features and the patient's age. [14]

Acute complications (torsion, rupture, bleeding) are more common with sizes >50-70 mm or dense/heavy lesions (e.g., dermoid). Localization on the right increases clinical suspicion for torsion and the need to differentiate it from appendicitis. [15]

In postmenopause, most simple unilocular cysts with a thin wall and a diameter <50 mm with a normal CA-125 are benign but require surveillance according to RCOG/SRU. The key is to look for solid components, papillary outgrowths, papillary blood flow, and ascites. [16]

Risk factors

Reproductive age and ovulatory cycles are a background "risk" for functional cysts; the incidence is influenced by ovulation variations, ovulation stimulation, and polycystic ovary syndrome (most often multiple follicles, not cysts per se). Corpus luteum cysts are frequently detected in pregnant women, which usually regress by 12-16 weeks. [17]

The risk of torsion is higher with cysts >50-70 mm, with dermoid cysts, and in pregnant women; torsion is more common on the right. This necessitates a low threshold for ultrasound/CT in acute right-sided pain. [18]

Postmenopause is a time for caution: the frequency of simple cysts is significant, but at the same time the underlying risk of ovarian cancer increases; therefore, it is in this group that standardized systems (O-RADS, IOTA) and the CA-125 marker in combination with imaging are particularly valuable. [19]

A family history of ovarian/breast cancer and carriage of pathogenic BRCA variants change the priorities and thresholds for intervention when complex cysts are detected; such patients are advised to consult an oncogynecologist for any questionable features on ultrasound. [20]

Table 3. What increases clinical risks

Factor	What's changing?
Cyst size >50-70 mm	Higher risk of torsion/rupture
Dermoid cyst	Severe → tendency to torsion
Postmenopause	Below the threshold of suspicion for cancer
BRCA/family history	Early referral to a gyneco-oncologist
Pregnancy (I-II trimester)	Corpus luteum cysts are common, most often observed [21]

Pathogenesis

A follicular cyst is the result of failed ovulation, when the dominant follicle fails to rupture and continues to accumulate fluid. Ultrasound reveals a thin-walled, anechoic structure without septa or solid elements; blood flow along the wall is peripheral. These cysts often resolve within 6-12 weeks. [22]

A corpus luteum cyst forms after ovulation and may have a thickened, hypervascular wall ("ring of fire") and intra-osseous echo clots during hemorrhage (hemorrhagic cyst). Important: hormonal contraceptives do not accelerate the resolution of an existing functional cyst. [23]

An endometrioma is a "chocolate" cyst with dense contents arising from ectopic endometrial tissue; a dermoid cyst is a mature teratoma with fatty inclusions and solid elements. These types have characteristic ultrasound features and a high chance of persistence, therefore they often require elective surgery if they grow or become symptomatic. [24]

Adnexal torsion occurs when the ovary and ligaments rotate around the vascular pedicle, leading to ischemia. Medium- and large-sized cysts predispose to this condition; right-sided torsions are more common, which is important for the management of right lower abdominal pain. [25]

Symptoms

Small functional cysts are usually asymptomatic and are discovered incidentally on ultrasound. Moderate "pulling" pain on the right side, a feeling of heaviness, and irregular menstruation may occur. With a hemorrhagic cyst, the pain may be more acute, sometimes accompanied by spotting. [26]

Torsion presents with sudden, severe, unilateral pain (usually on the right), often accompanied by nausea and vomiting; the pain may be constant or come in waves with spontaneous rotation or inversion of the appendages. This condition requires urgent diagnosis and, as a rule, emergency laparoscopy. [27]

A cyst rupture causes severe pain with possible signs of intra-abdominal bleeding: weakness, decreased blood pressure, and an acute abdomen. Hemoperitoneum most often accompanies rupture of corpus luteum cysts. Any sign of an acute abdomen requires immediate medical attention. [28]

Large, persistent cysts may cause mechanical symptoms, including frequent urination, discomfort during intercourse, and bloating. With right-sided pain, it's important to distinguish cysts from appendicitis, which is the initial diagnosis in the right iliac region in many patients. [29]

Classification, forms and stages

Clinically, it is convenient to divide cysts into functional (follicular, corpus luteum, including hemorrhagic) and nonfunctional (endometriomas, dermoid cysts, cystadenomas, paraovarian). This approach immediately determines the likelihood of spontaneous regression and the need for intervention. [30]

For visualization, the IOTA lexicon and the O-RADS US v2022 system are used: based on a set of characteristics (simplicity/complexity, septa, papillae, solid areas, blood flow, ascites), the formation is assigned a category 0-5 and a corresponding recommendation (observe, refer to an oncogynecologist, etc.). This standardizes decisions and reduces the number of unnecessary operations. [31]

A separate role is played by “simple cysts” (thin-walled, anechoic, without septa and solid elements): in premenopause ≤50 mm usually do not require monitoring or are monitored once every 6-12 weeks; in postmenopause <50 mm and normal CA-125 - conservative management. [32]

During pregnancy, most uncomplicated cysts are observed; indications for surgery include persistent pain, growth, suspicion of malignancy, or complications (torsion/rupture). The best "window" if necessary is the second trimester. [33]

Table 4. Ultrasound classification (very briefly)

System	What does it evaluate?	Practical meaning
IOTA Simple Rules	5 "benign" and 5 "malignant" signs	Rapid risk stratification using ultrasound
O-RADS US v2022	Risk categories 0-5	Observation/Direction Algorithms
SRU Consensus	Size thresholds and follow-up	Who and when should undergo a follow-up ultrasound [34]

Complications and consequences

The two main complications are torsion and rupture/bleeding. Torsion poses a risk of ovarian ischemia; even with a "questionable" Doppler image, clinical findings are more important, and delay worsens the chances of preserving the organ. Right-sided torsions are more common. [35]

Rupture of a cyst (especially a corpus luteum cyst) can lead to hemoperitoneum and requires hospital observation or surgery depending on the hemodynamics and blood volume in the abdominal cavity. In a stable condition, conservative management under ultrasound/hemoglobin monitoring is often possible. [36]

Long-standing large cysts cause chronic pelvic pain, dyspareunia, dysuria, and constipation due to pressure on adjacent organs. Endometriomas are associated with infertility; dermoids require removal if they grow and twist. [37]

Oncologic transformation is characteristic not of functional cysts, but of true tumors (e.g., cystadenocarcinoma). Early identification by ultrasound features and referral to a gynecologic oncologist are important, especially in postmenopausal women. [38]

When to see a doctor

Immediately - if you experience sudden, severe pain in the lower right abdomen, nausea/vomiting, fainting, or fever: these are signs of torsion or rupture. These symptoms require emergency care and imaging. [39]

In the coming days, if new nagging pain on the right side, bloating, menstrual irregularities, or painful intercourse develop, these are reasons to schedule a routine ultrasound and gynecological examination to determine the type of cyst and further treatment. [40]

Planned - if a cyst is accidentally discovered on ultrasound, the doctor will explain whether follow-up is necessary. Small, simple cysts in premenopause often do not require follow-up; if the cyst size is 50-70 mm, a follow-up is usually scheduled in 6-12 weeks, and if it is >70 mm, surgery is considered. [41]

During pregnancy, any pain on the right side, especially with nausea/vomiting, should be considered, especially torsion and appendicitis. Most uncomplicated cysts are monitored, but the urgency criteria remain the same. [42]

Diagnostics

Step 1. Collection of complaints and examination. The doctor clarifies the nature of the pain (sharp/wave-like), its relationship to the cycle, symptoms of peritoneal irritation, checks for pregnancy, and rules out appendicitis in cases of right-sided pain. The examination is supplemented by bimanual palpation. [43]

Step 2. Basic tests. For pregnant women/suspected pregnancy - quantitative β-hCG; complete blood count; if there is a fever - C-reactive protein. The CA-125 tumor marker is useful mainly in postmenopause and in cases of suspected cancer; in premenopause, it has low specificity (increases in endometriosis and inflammation). [44]

Step 3. Visualization. The "gold standard" is transvaginal ultrasound with Doppler using the IOTA lexicon. The description is converted to the O-RADS US v2022 category to obtain a standard recommendation (observation, CT/MRI, consultation with a gynecologic oncologist). In case of doubt, large size, or atypia, pelvic MRI is used. [45]

Step 4. Decision and dynamics. Simple cysts in premenopause ≤50 mm usually do not require repeat examinations; 50-70 mm - control ultrasound after 6-12 weeks; >70 mm - discussion of surgery due to the risk of torsion. In postmenopause, simple cysts <50 mm with a normal CA-125 are monitored at intervals of 4-6 months, then annually. [46]

Table 5. Diagnostic route (briefly)

Situation	What are we doing?
Sharp right side pain, nausea/vomiting	Urgent ultrasound/CT scan to rule out torsion/rupture, appendicitis
Incidental simple cyst ≤50 mm (premenopause)	Usually without repetitions
Simple cyst 50-70 mm	Follow-up ultrasound in 6-12 weeks
Simple cyst >70 mm or complex cyst	Consider laparoscopy; oncoconsultation if suspected
Postmenopause, simple cyst <50 mm, CA-125 normal.	Outpatient observation 4-6 months → annually [47]

Differential diagnosis

With right-sided pain, appendicitis is the first thing to rule out. It is characterized by pain shifting from the umbilical region to the right, worsening with coughing and walking, and fever. However, clinical signs can be vague, and ultrasound/CT scans are the final solution. Cysts and torsion often mimic appendicitis, so collaboration between a surgeon and a gynecologist is essential. [48]

Functional cysts are differentiated from endometriomas ("finely dispersed contents," "ground-glass"), dermoids (fat, calcifications, solid components), paraovarian cysts (outside the ovarian tissue), and tubo-ovarian abscesses (fever, pain, elevated inflammatory markers). Ultrasound features according to IOTA are very helpful in narrowing the range. [49]

In pregnant women, consideration is also given to right-sided colic, urolithiasis, and, of course, torsion—one of the common non-obstetric causes of an "acute abdomen" during gestation. The decision is made through a multidisciplinary approach. [50]

In postmenopausal women, solid areas, papillary growths, thick septa, ascites, and elevated CA-125 are reasons for urgent referral to a gynecologic oncologist. Here, O-RADS/IOTA sets clear "red flags." [51]

Treatment

For small, uncomplicated functional cysts in premenopausal women, the basic approach is watchful waiting: a follow-up ultrasound scan after 6-12 weeks, followed by clinical evaluation. Most such cysts (especially those ≤50 mm) resolve spontaneously; however, hormonal contraceptives do not accelerate the resolution of existing cysts, as confirmed by randomized trials and a Cochrane meta-analysis. [52]

Pain relief includes nonsteroidal anti-inflammatory drugs, antispasmodics, and heat. In the case of a hemorrhagic cyst and stable hemodynamics, a conservative approach is acceptable, with ultrasound and hemoglobin monitoring being monitored; deterioration is a reason for laparoscopy (coagulation/excision of the bleeding lesion, abdominal debridement). [53]

In premenopausal women, the risk of torsion and rupture increases with cysts larger than 70 mm. Elective laparoscopy with cystectomy is often chosen, with an effort to preserve ovarian tissue. The exception is a "perfectly simple" cyst without complaints in a patient who categorically does not want surgery: in this case, the decision is individualized, but the risks are discussed in detail. [54]

Endometriomas are treated with consideration for reproductive plans. Before a planned pregnancy/IVF, removal of an endometrioma ≥30-40 mm is often recommended (to reduce pain and facilitate access to follicles during puncture), but this is due to the loss of ovarian reserve; small asymptomatic lesions can be observed. Postoperatively, hormonal suppression is recommended to reduce the risk of recurrence if pregnancy is not planned "immediately." [55]

Dermoid cysts (mature teratomas) are prone to growth and torsion; if they are larger than 50 mm and/or symptomatic, laparoscopic cystectomy is recommended. It is important to avoid spillage of contents (fat and hair) and thoroughly lavage the abdominal cavity to prevent chemical peritonitis. Rarely, oophorectomy is appropriate for multiple large dermoids. [56]

In postmenopausal women, simple unilocular cysts <50 mm with a normal CA-125 level are managed conservatively with ultrasound monitoring (the first time is after 4-6 months, then annually). Any complex symptoms or growth require referral to a gynecologic oncologist and surgical treatment at a specialized center. Minimally invasive approaches are preferred when possible. [57]

Most cysts are observed during pregnancy. Indications for surgery include suspected cancer, torsion, rupture, persistent pain, and rapid growth. The optimal time for planned laparoscopy is 16-20 weeks; in case of torsion, the procedure is performed urgently at any time, with priority given to preserving the ovary (detorsion and fixation if necessary). [58]

Adnexal torsion is an emergency: the standard procedure is urgent laparoscopy with detortion and viability assessment. Even a "blue" ovary often recovers, so organ preservation is a priority; simultaneous cystectomy is performed if safe. Right-sided torsion is more common—consider this when triaging right-sided pain. [59]

Cyst aspiration as a "treatment" is not recommended due to the high risk of recurrence (up to 53-83%), except in certain palliative cases and for functional cysts in patients with contraindications to surgery. Complete cystectomy with capsule removal is preferred. [60]

The role of hormonal therapy. Combined contraceptives do not accelerate the resolution of existing functional cysts, but they can reduce the occurrence of new ones by suppressing ovulation. This is considered in patients with recurring painful episodes. The decision is personalized based on contraindications and reproductive plans. [61]

Table 6. Tactics by type/situation (simplified)

Scenario	Recommended	Explanation
Simple cyst ≤50 mm (premenopausal)	Observation	Often regression within 6-12 weeks
Simple cyst 50-70 mm	Follow-up 6-12 weeks → discussion	In case of growth/symptoms - laparoscopy
Simple cyst <50 mm (postmenopause), CA-125 normal.	Observation for 4-6 months, then annually	RCOG/SRU
Endometrioma ≥30-40 mm	Cystectomy for IVF plans/pain	Take into account the reserve
Dermoid >50 mm/symptoms	Laparoscopic cystectomy	Avoid spillage
Torsion	Urgent laparoscopy, detorsion	Right-sided - more often
Pregnancy, uncomplicated cyst	Observation	Surgery for strict indications [62]

Prevention

There is no specific “prevention” for functional cysts, but the risk of complications can be reduced: do not delay a visit if sudden one-sided pain occurs, perform control ultrasounds according to recommendations, plan surgery for large persistent cysts to reduce the likelihood of torsion. [63]

Hormonal contraception can reduce the incidence of new functional cysts by suppressing ovulation, but it does not treat existing cysts. The decision to use it is individualized, after discussing the benefits/risks and reproductive plans. [64]

With endometriosis, endometrioma recurrences are lower with hormonal suppression after surgery (if there are no immediate plans to become pregnant). Maintaining an active lifestyle, weight control, and treatment of pelvic inflammatory diseases reduce the underlying risks of pain and complications. [65]

Postmenopausal women benefit from routine ultrasound examinations as indicated and careful attention to symptoms; for any “complex” cyst, an early consultation with an oncogynecologist is recommended. [66]

Forecast

The vast majority of patients with functional cysts have an excellent prognosis: the cysts resolve without intervention, and fertility is not affected. Proper risk stratification is important to avoid treating "just in case" and to avoid missing rare oncological processes. [67]

Even with complications, timely laparoscopy allows for ovarian preservation and restoration of function. Torsion is not a death sentence for the organ: modern data emphasize the benefits of organ-preserving detorsion. [68]

For endometriomas and dermoids, the prognosis depends on the size, symptoms, and quality of surgery; recurrences are possible, but their incidence is reduced with proper technique and subsequent hormonal prophylaxis (if pregnancy is not planned). [69]

In postmenopause, simple small cysts and normal CA-125 are associated with a very low risk of cancer; regular surveillance is safe and cost-effective. [70]

FAQ

Is a right-sided cyst more dangerous than a left-sided one?
Not in itself, but adnexal torsion more often occurs on the right side due to anatomy. Therefore, with acute right-sided pain, the threshold for an urgent ultrasound is lower. [71]

Do "pills" help resolve cysts?
No: combined contraceptives do not speed up the resolution of an existing functional cyst. They are being discussed for reducing the incidence of new cysts and for cycle control. [72]

When to operate?
For large (>70 mm) or growing cysts, a "complex" structure according to O-RADS/IOTA, symptoms, suspicion of cancer, and complications (torsion, rupture). In postmenopausal women, the thresholds are lower, and the decision is made by the gynecologic oncology team. [73]

Can a cyst be confused with appendicitis?
Yes. With right lower abdominal pain, appendicitis is the first diagnosis. Ultrasound/CT and a joint assessment by a surgeon and gynecologist help quickly make the correct diagnosis and choose the appropriate treatment. [74]

What to do during pregnancy?
Most uncomplicated cysts are monitored; they often regress. Surgery is necessary if cancer, torsion, rupture, persistent pain, or growth are suspected; the optimal time for elective laparoscopy is the second trimester. [75]