Ovarian cysts

Ovarian cysts are fluid-filled sacs within the ovary. The most common types are functional follicular cysts, corpus luteum cysts, and theca lutein cysts, which all develop as part of the menstrual cycle and are usually harmless and resolve on their own. Nonfunctional cysts include chocolate cysts (which are associated with endometriosis), dermoid cysts, cystadenomas, and malignant cysts (a type of ovarian cancer). Ovarian cysts are usually asymptomatic, but they can sometimes cause lower abdominal pain and predispose individuals to complications such as cyst rupture or ovarian torsion, which may require surgery. Diagnosis is usually made with pelvic ultrasound. Management and follow-up depend on cyst size and appearance on ultrasound, the patient's menopausal status, and the presence of risk factors for ovarian tumors.

Definition

Ovarian cysts are fluid-filled sacs within the ovary.

Types

Functional ovarian cysts

Functional cysts result from a disruption in the development of follicles or the corpus luteum and often resolve on their own.

• Follicular cyst of the ovary (most common ovarian mass in young women)
  • Develops when a Graafian follicle does not rupture and release the egg (ovulation) but continues to grow
  • Eventually develops into a large cyst (∼ 7 cm) lined with granulosa cells
  • Associated with hyperestrogenism and endometrial hyperplasia
• Corpus luteum cyst
  • Enlargement and buildup of fluid in the corpus luteum after failed regression following the release of an ovum
  • Produces progesterone, which may delay menses
  • Associated with progesterone-only contraceptive pills and ovulation-inducing medication
  • Common during pregnancy
• Theca lutein cysts
  • Often multiple cysts that typically develop bilaterally
  • Result from exaggerated stimulation of the theca interna cells of the ovarian follicles due to excessive amounts of circulating gonadotropins such as β-hCG
  • Strongly associated with gestational trophoblastic disease and multiple gestations
  • Usually resolve once β-hCG levels have normalized

Nonfunctional ovarian cysts

A group of ovarian cysts that do not produce hormones.

• Chocolate cysts
• Dermoid cysts
• Cystadenoma (serous or mucinous)
• Malignant cysts (form of ovarian cancer): higher risk in postmenopausal women

• Usually asymptomatic (incidental finding)
• Can cause lower abdominal pain and lead to complications ^[1]
• Adnexal mass that is sometimes palpable
• Possibly signs of the underlying cause, such as:
  • Menorrhagia in endometriosis
  • Hirsutism, acne, and infertility in polycystic ovary syndrome

Ovarian cancer must be ruled out in premenarchal and postmenopausal patients with a palpable ovarian mass.

Approach

• First-line imaging: pelvic ultrasound ^[2][3]
• For suspected malignancy ^[3][4]
  • Consider repeat ultrasound by expert sonographer or with MRI.
  • See also “Diagnostics for ovarian cancer.”
• For acutely symptomatic patients ^[2][5]
  • Rule out pregnancy with serum or urine β-hCG test.
  • Consider CT to rule out nongynecologic causes and complications.
  • Perform additional diagnostics as clinically indicated; see “Approach to acute abdomen.”

Exclude pregnancy in all patients of childbearing age with pelvic pain or a pelvic mass. ^[5]

Laboratory studies ^[5]

• Urine or serum β-hCG: to rule out ectopic pregnancy
• CBC: to evaluate for hemorrhage

Imaging

Pelvic ultrasound with doppler

Transvaginal or transabdominal pelvic ultrasound with doppler is the first-line imaging modality for symptomatic and asymptomatic patients with a suspected adnexal mass.

• Simple cysts ^[6]
  • Smooth lining on all sides
  • Single: e.g., follicular cyst of the ovary, corpus luteum cyst
  • Multiple: e.g., polycystic ovary syndrome, multilocular theca lutein cysts
  • Anechoic
  • No internal flow on Doppler
• Corpus luteum cyst ^[7]
  • Unilocular cyst with thick walls
  • ↑ Peripheral vascularity (ring-of-fire sign)
  • Small central lucency
  • Intracystic echogenic debris may be present.
• Theca lutein cysts ^[8]
  • Bilateral multilocular cysts with thin walls
  • Fluid-filled
  • Solid components may be present.
• Potentially malignant cysts ^[4]
  • Multilocular cysts with solid components
  • Solid irregular masses
  • Ascites and/or peritoneal nodules
  • See also “Overview of ovarian tumors.”

Additional imaging ^[5]

• MRI pelvis with IV contrast
  • Indicated for further evaluation of potentially malignant cysts
  • Consider in patients with acute pelvic pain and contraindications for CT (e.g., pregnancy).
• CT abdomen and pelvis with IV contrast
  • Alternative to MRI for potentially malignant cysts
  • Consider in patients with acute pelvic pain to rule out nongynecologic etiologies.

• Ectopic pregnancy
• Tubo-ovarian abscess
• Ovarian tumors

The differential diagnoses listed here are not exhaustive.

Management and follow-up are usually determined by cyst appearance and size as well as menopausal status. ^[5][6]

• All patients
  • Pain management: NSAIDs (first-line), opioids (only for severe cases)
  • Treatment of underlying conditions such as polycystic ovary syndrome or endometriosis
  • Refer for outpatient follow-up with a gynecologist.
  • Consider gynecology consult prior to discharge for potentially malignant cysts.
• Functional cysts
  • Watchful waiting with repeat ultrasound
  • Oral contraceptives are not routinely recommended. ^[9]
• Complications, large cysts, persistent painful cysts: Consider surgery.

In most patients with functional cysts, watchful waiting is recommended, as cysts often regress spontaneously.

• Ovarian torsion
• Ruptured ovarian cyst
• Hemorrhage

We list the most important complications. The selection is not exhaustive.

Etiology ^[11]

• Rupture is caused by an increase in intracystic pressure.
• Most common type of ruptured cyst: corpus luteum cyst ^[12]
• Risk factors
  • Vigorous physical activity
  • Vaginal intercourse
  • Large cysts
  • Reproductive age

Clinical features

• May be asymptomatic
• Sudden-onset unilateral lower abdominal pain ^[10]
• Possible signs of peritonitis ^[5]
• Possible nausea and vomiting ^[10]
• Minimal vaginal bleeding (spotting) may occur in some cases.
• In case of significant hemorrhage: hypovolemic shock ^[10]

Diagnostics ^[10]

Laboratory studies

• Urine or serum β-hCG: obtain in all patients to exclude intrauterine or ectopic pregnancy
• CBC: may show anemia
• Emergency preoperative diagnostics: coagulation panel, type and screen

Imaging

• POCUS/FAST: Consider in unstable patients to rapidly assess for the presence and extent of free fluid.
• Transabdominal/transvaginal pelvic ultrasound: imaging modality of choice
  • Characteristic findings ^[10][12]
    • Free fluid, most commonly in the pouch of Douglas (rectouterine pouch) ^[2][5]
    • An adnexal mass may be visualized if the cyst is large.
  • Disadvantage: cannot reliably distinguish between ruptured ovarian cyst or ruptured ectopic pregnancy in a pregnant patient. ^[13]
• CT pelvis with IV contrast: consider in nonpregnant patients if ultrasound findings are inconclusive
  • Characteristic findings: pelvic hemoperitoneum ^[13]

Free fluid in the pouch of Douglas in a pregnant patient should raise concern for ruptured ectopic pregnancy.

Treatment ^[10][14][15]

• Hemodynamically unstable patients: : emergency exploratory laparoscopy/laparotomy to obtain hemostasis
  • Suturing or cauterization of the ruptured section or cystectomy
  • Consider oophorectomy in intractable hemorrhage
• Hemodynamically stable patients: conservative management with analgesics and observation
  • Consider outpatient monitoring with close follow-up for patients with:
    • Minimal hemoperitoneum
    • Stable Hb on serial monitoring over 4–6-hours ^[16]
  • Inpatient management if there is evidence of significant and/or ongoing hemorrhage ^[10]
    • Monitor vital signs, hemoglobin, and hemoperitoneum size on ultrasound.
    • Consider laparoscopy if there is concern for ongoing hemorrhage.
• All patients: Consider blood transfusion as needed.

Differential diagnoses

• Mittelschmerz
• Ruptured or bleeding ectopic pregnancy
• Tubo-ovarian abscess
• Ovarian torsion
• Acute appendicitis
• Diverticulitis
• See also: “Differential diagnosis of lower abdominal pain in young women.”

Acute management checklist for ruptured ovarian cyst

• Urgent OB/GYN consult
• NPO
• IV fluids (see IV fluid therapy)
• Parenteral analgesics: Opioid analgesics are preferred.
• Order emergency preoperative diagnostics and β-hCG.
• Obtain consent for blood transfusion and give emergent transfusion in suspected hemorrhagic shock.
• Hemodynamically unstable patients: emergency exploratory surgery for hemostasis
• Hemodynamically stable patients: Monitor vitals, Hb, and size of hemoperitoneum on imaging.