AKT · Obstetrics & gynaecology/Menstrual & benign gynae

Ovarian cysts

Functional or neoplastic adnexal cyst

Overview

Fluid-filled ovarian structures — usually benign functional cysts in premenopausal women (follicular/corpus luteal). Risk-of-malignancy (RMI) stratification and the menopausal status guide management; complications include rupture, haemorrhage and torsion.

Recognise

Often asymptomatic; dull pelvic pain, bloating, pressure
Acute pain if rupture/haemorrhage/torsion
Premenopausal simple cysts usually functional and self-resolving

Red flags

Features of malignancy (solid/multilocular, ascites, raised CA125, postmenopausal), or acute torsion/rupture with shock

Differentials & how to tell them apart

Ovarian torsionacute severe unilateral pain, nausea, tender adnexal mass — emergency

Ectopic pregnancypositive βhCG, pain + bleeding

Ovarian cancercomplex/solid mass, ascites, raised CA125, older

Endometrioma"chocolate cyst", cyclical pain

Investigations

Transvaginal USS characterises the cyst; CA125 (with caution — raised in many benign conditions too); Risk of Malignancy Index (RMI = USS score × menopausal status × CA125).

Management

Conservative follow-up for simple premenopausal cysts (<5 cm)

1Premenopausal simple cyst <5 cm: no action (physiological). 5–7 cm: yearly USS.Gate: Postmenopausal, or complex/large/raised CA125 (high RMI) → refer to gynae-oncology
2Symptomatic, large or suspicious: laparoscopic cystectomy/oophorectomy.

Conservative/expectant — simple premenopausal cysts — repeat USS

Surgery (cystectomy) — large, persistent, symptomatic or suspicious

Key points

Always exclude torsion and ectopic in acute pain. Premenopausal functional cysts usually resolve over 2–3 cycles.

Monitor & prognosis

Serial USS; symptoms.

Most benign and self-resolving.

Source: RCOG; NICE