What is the recommended treatment for a simple cyst of the ovary?

Management of Simple Ovarian Cysts

Simple ovarian cysts up to 10 cm in diameter can be safely managed conservatively without surgical intervention in both premenopausal and postmenopausal women, with management strategy determined by patient menopausal status and cyst size. 1

Risk of Malignancy

Simple ovarian cysts carry an extremely low malignancy risk, classified as O-RADS 2 (almost certainly benign, <1% risk of malignancy). 1 The evidence supporting conservative management is robust:

• In premenopausal women under 50 years: Zero cases of cancer were found among 12,957 simple cysts over 3 years of follow-up 1
• In postmenopausal women over 50 years: Only 1 malignancy was identified among 2,349 simple cysts (0.04%) 1
• Recent studies confirm: Malignancy occurs exclusively in complex cysts, not simple cysts, in both menopausal groups 2

Management Algorithm by Menopausal Status

Premenopausal Women

Cysts ≤3 cm:

• Consider physiologic (normal follicles) 1
• No follow-up required 1

Cysts >3 cm to ≤5 cm:

• No additional management required 1
• These are likely functional and will resolve spontaneously 1

Cysts >5 cm to <10 cm:

• Follow-up ultrasound in 8-12 weeks to confirm functional nature or reassess for wall abnormalities 1, 3
• Optimal timing: during proliferative phase (after next menstrual period) to allow functional cysts to involute 1, 3
• If cyst persists or enlarges: refer to gynecologist 1, 3
• If cyst resolves or decreases: no further action needed 1

Postmenopausal Women

Cysts ≤3 cm:

• No further management required 1
• These carry negligible malignancy risk 1, 4

Cysts >3 cm to <10 cm:

• At least 1-year follow-up showing stability or decrease in size 1
• Consider annual follow-up for up to 5 years if stable 1
• If cyst enlarges: refer to gynecologist 1

Important Caveats

Ensure accurate characterization: The cyst must be truly "simple" - unilocular, anechoic, smooth thin wall, acoustic enhancement, and absolutely no internal elements, solid components, or septations. 1 Any deviation from this morphology reclassifies it as a complex cyst requiring different management. 2

Size limitations: For cysts approaching 10 cm, transvaginal ultrasound may incompletely evaluate the cyst wall. 1 Perform transabdominal examination or consider MRI if wall abnormalities cannot be excluded. 1

CA-125 is not routinely indicated: For simple cysts meeting ultrasound criteria, tumor markers add minimal value and are not recommended as part of routine management. 5, 2 CA-125 has poor positive predictive value (0.35) for malignancy in this context. 2

Surgery is NOT indicated for simple cysts <10 cm that meet strict ultrasound criteria, regardless of menopausal status, per American College of Obstetricians and Gynecologists guidelines. 1, 6