Clinical context
Ovarian cysts are a common finding in gynaecological clinical practice, mostly identified by pelvic ultrasound and often incidentally. Their high prevalence, particularly in women of reproductive age, contrasts with the concern they frequently generate, usually related to fear of malignancy or acute complications. Although, in most cases, they correspond to benign and self-limited lesions, their correct interpretation requires a structured approach capable of distinguishing low-risk situations from those requiring closer surveillance or specialist referral.
Initial assessment
Assessment should always begin with the clinical presentation, with particular attention to the presence of red flags. Sudden and intense pelvic pain, associated nausea or vomiting, peritoneal signs, haemodynamic instability or fever should raise suspicion of acute complications, such as adnexal torsion or cyst rupture, both of which are gynaecological emergencies requiring immediate hospital assessment. In women of reproductive age, pregnancy must be excluded, particularly ectopic pregnancy, which may present in a similar way.
Importance of menopausal status
In the absence of emergency criteria, menopausal status plays a central role in interpreting the ultrasound finding. In premenopausal women, most simple cysts correspond to functional cysts related to the ovulatory cycle, with a high probability of spontaneous resolution. In postmenopausal women, although many cysts remain benign, the baseline risk of malignancy is higher, justifying a more cautious approach and stricter risk stratification.
Ultrasound characteristics
Transvaginal ultrasound is the first-line examination and allows characterisation of cyst morphology. Unilocular, anechoic lesions with thin and regular walls, without thick septations, papillary projections or solid components, generally have a low risk of malignancy. Conversely, the presence of thick septations, papillary projections, vascularised solid components, ascites or bilaterality should increase suspicion, regardless of the patient’s age, and justify specialist assessment.
Approach in premenopausal women
In premenopausal women, small, simple and asymptomatic cysts rarely require prolonged follow-up. When the cyst is larger or persists over time, ultrasound reassessment allows documentation of resolution, stability or progression. Typical haemorrhagic cysts tend to evolve favourably and may be followed conservatively, while endometriomas and dermoid cysts should be reassessed if they are symptomatic, increase in size or present indeterminate features.
Approach in postmenopausal women
In postmenopausal women, even cysts with simple morphology may justify additional assessment, especially when they exceed certain size thresholds or are associated with symptoms. CA-125 measurement may be useful in this context, provided it is interpreted together with the clinical presentation and ultrasound findings, recognising its limitations. The combination of suspicious ultrasound findings, persistent symptoms and laboratory abnormalities indicates a significantly increased risk of malignancy.
Surveillance and follow-up
When surveillance is considered appropriate, it should be rational and time-limited. The aim is to confirm spontaneous resolution or stability of the lesion, avoiding indefinite follow-up of benign findings. A cyst that remains stable in size and morphology over a prolonged period, in the absence of relevant symptoms, allows follow-up to be safely discontinued, reducing unnecessary examinations and unjustified anxiety.
Specialist referral
Persistent symptoms, cyst growth, morphological changes or an overall increase in risk should prompt referral to Gynaecology. In cases where there is significant suspicion of malignancy, specialist assessment, ideally in a gynaecological oncology setting, is essential to optimise the diagnostic and therapeutic approach and improve prognosis.
