RCOG Ovarian Masses in Premenopausal Women, Management of Suspected (Green-top Guideline No. 62). Last reviewed: Dec 2011.
Article Last Updated: 21 April 2026
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Ovarian Cysts
Ovarian cysts are fluid-containing structures within or on the ovary, and many are benign, incidental, and self-limiting.
Updated UKMLA guide to ovarian cysts, based primarily on RCOG guideline: classification, symptoms, investigation, management, and complications.
Ovarian cysts are a broad and heterogeneous topic. Different cyst types have their own clinical associations, characteristic features, and imaging findings.
However, detailed subtype-specific distinctions are usually not required at a non-specialist level and are therefore omitted here.
The key learning points are understanding ovarian cysts as a whole, their general assessment and management principles, and recognising features that may suggest malignancy (ovarian cancer).
Suspected cancer pathway referral is indicated in the presence of:
Ascites, and/or
Pelvic or abdominal mass (which is not obviously uterine fibroids)
For further information, see the Ovarian Cancer article.
Assessment
If a female of reproductive age presents with abdominal or pelvic pain and/or pelvic mass, a pregnancy test should be performed as part of the immediate steps.
1st line investigation: TVUSTrans-vaginal ultrasound
A simple / functional cyst would typically have a thin-walled cyst without any internal structures
Benign ultrasound findings
Malignant ultrasound findings
Unilocular cyst
Smooth multilocular tumours <100 mm
Presence of acoustic shadowing
Solid components <7 mm
No blood flow
Irregular solid tumour
Ascites
Irregular multilocular solid tumour >100 mm
At least 4 papillary structures
Strong blood flow
If ANY of the malignant ultrasound findings listed above are present → refer to secondary care for query ovarian cancer (see the Ovarian Cancer article for more information)
Further imaging (CT / MRI) is only indicated if there are malignant findings or benign findings but >70 mm.
Management
Common management approach for presumed benign simple cysts:
Conservative (expectant) management
Surgical management
Indications
Simple cysts that are <70 mm in diameter
Symptomatic cyst (esp. pain)
Large cysts (>70 mm)
Persistent cysts (cysts that do NOT resolve after menstrual cycles are unlikely to be simple / functional)
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