Synopsis
Turn an unexpected adnexal finding into a safe age- and morphology-specific plan, avoiding both unnecessary intervention for low-risk simple cysts and delayed referral of complex or malignant disease.
- Verify the finding: obtain the original report and images, determine organ of origin, record maximum size and morphology, and establish whether the whole lesion was visible on CT, MRI or ultrasound.
- Ask about pain, bloating, early satiety, urinary symptoms, bleeding, pregnancy possibility, menopause, endometriosis, fertility treatment, previous cancer and family history before calling a mass asymptomatic.
- In premenopausal adults, a truly simple cyst smaller than 50 mm generally needs no follow-up; 50–70 mm simple cysts receive yearly ultrasound, while larger lesions merit MRI or surgical assessment.
- In postmenopausal adults, RCOG's December 2025 update states that an asymptomatic unilateral unilocular simple cyst 3 cm or smaller needs no routine follow-up.
- A postmenopausal simple unilateral unilocular cyst larger than 3 cm and up to 5 cm with normal CA125 can be reassessed in 4–6 months and discharged after one year if unchanged or smaller with normal CA125.
- Postmenopausal symptoms, non-simple features, size above 5 cm, multilocularity or bilaterality move the lesion out of the low-risk conservative branch and into surgical or oncology assessment.
- Use transvaginal ultrasound for definitive morphology when an incidental CT or MRI finding is not already diagnostic; add transabdominal views for large lesions.
- Assign every observation plan to a named clinician, specify the interval and endpoint, and provide urgent safety-netting rather than writing repeat scan without ownership.
Key red flags
Irregular solid tissue, papillary projections, ascites, metastases, strong vascularity, multilocular-solid morphology or bilateral complex lesions requires urgent specialist malignancy assessment.
Persistent bloating, early satiety, pelvic or abdominal pain, urinary urgency or frequency and unexplained weight loss can make an incidental lesion clinically suspicious, especially after menopause.
Acute unilateral pain with vomiting can be torsion despite a benign earlier report or preserved Doppler flow and needs urgent surgical review.
A positive pregnancy test with pain, bleeding or free fluid requires pregnancy-location assessment rather than routine cyst surveillance.
A complex mass in a patient under 40 needs germ-cell marker assessment and specialist triage; a normal CA125 alone is not reassuring.
Investigation priorities
Verify organ of origin, dimensions, morphology, temporal comparison and whether the entire lesion was visualised.
Management branches
CT, MRI or non-specialist ultrasound reports an unexpected adnexal lesion.
- Retrieve the report and images, compare prior studies and confirm size, laterality, menopausal status, symptoms and pregnancy possibility.
- Arrange expert transvaginal ultrasound with transabdominal supplementation unless the existing study already provides adequate definitive characterisation.
- Route acute symptoms immediately and assign the non-acute result to a named clinician who will communicate the plan.