Ovarian Cysts — Types, Symptoms, Diagnosis & Management Guide — Symptoms, Causes & Treatment | MyMedicPlus

Ovarian cysts are fluid-filled or semi-solid sacs that develop on or within the ovaries. They are extremely common — functional ovarian cysts (related to the normal menstrual cycle) occur in the majority of menstruating women at some point during their reproductive years, and most resolve spontaneously within 6-12 weeks without treatment. The clinical challenge lies in distinguishing the vast majority of benign functional or benign morphological cysts from the small minority of malignant or borderline tumours that require surgical management. The lifetime risk of ovarian cancer is approximately 1-2% — but approximately 1 in 1,000 women referred with a persistent ovarian cyst has a malignancy. The RCOG (Royal College of Obstetricians and Gynaecologists) Green-top Guidelines and the Risk of Malignancy Index (RMI) provide evidence-based frameworks for stratifying risk and guiding management decisions.

Functional cysts (most common, benign): follicular cysts (from a follicle that fails to rupture at ovulation — usually resolve within 2-3 menstrual cycles; below 3 cm usually asymptomatic); corpus luteum cysts (from the post-ovulation corpus luteum — can cause pain, occasionally bleed, resolve within 4-6 weeks). Endometriomas ('chocolate cysts'): cysts containing old blood from ectopic endometrial tissue (endometriosis) — most common complex cyst in women of reproductive age; characteristic 'ground glass' appearance on ultrasound; require cystectomy. Dermoid cysts (mature teratomas): most common benign neoplasm in women under 45; contain multiple tissue types (hair, teeth, sebaceous material); bilateral in 10-15%; have a small risk of torsion; require laparoscopic cystectomy. Serous and mucinous cystadenomas: benign epithelial neoplasms — serous cystadenomas are most common ovarian tumour overall; remove surgically. Polycystic ovaries (PCO): multiple small follicular cysts bilaterally on ultrasound — a morphological finding associated with PCOS (polycystic ovary syndrome); not the same as an ovarian cyst requiring treatment. Malignant ovarian tumours: most are epithelial (serous high-grade, endometrioid, clear cell, mucinous, borderline); non-epithelial tumours include sex cord-stromal (granulosa cell) and germ cell tumours.

Most ovarian cysts — particularly small functional cysts — are completely asymptomatic and discovered incidentally on ultrasound performed for another indication (pelvic pain, fertility assessment, abdominal examination). When symptoms occur: pelvic or lower abdominal pain — ranging from a dull aching to sharp pain; pain may be unilateral, related to the side of the cyst. Bloating, fullness, and pressure in the lower abdomen. Dyspareunia (deep pain during intercourse). Urinary symptoms if the cyst impresses on the bladder (frequency, incomplete emptying). Menstrual disturbance — particularly with functional cysts or endometriomas. Torsion of the ovary (ovarian torsion): sudden onset severe unilateral pelvic pain, often with nausea and vomiting — a surgical emergency; cysts above 5 cm and dermoid cysts have the highest torsion risk. Rupture of an ovarian cyst: acute sharp pain, may be associated with intraperitoneal bleeding (haemoperitoneum from corpus luteum rupture — can cause haemodynamic instability). Hormonal symptoms from functional or stromal tumours: virilisation (granulosa cell or Leydig cell tumours), or precocious puberty in girls.

Transvaginal ultrasound (TVUS): the primary investigation — characterises the cyst by size, morphology (simple unilocular vs complex — multilocular, solid elements, papillary projections, septations, nodularity, acoustic shadowing — dermoid), and presence of free fluid. IOTA (International Ovarian Tumour Analysis) classification system and simple rules provide objective ultrasound-based risk stratification: Simple Rules classify cysts as benign (M features) or malignant (B features) — refer to a cancer centre if inconclusive. CA-125: a serum tumour marker elevated in epithelial ovarian cancer — also elevated in endometriosis, PID, pregnancy, and other conditions (low specificity). CA-125 is not a standalone diagnostic test. Risk of Malignancy Index (RMI): calculated from CA-125, menopausal status, and ultrasound score (U) — RMI above 250 warrants referral to a gynaecological oncology MDT. HE4 (human epididymis protein 4): more specific than CA-125 for ovarian cancer; ROMA score combines CA-125 and HE4 for pre/post-menopausal risk stratification. CT or MRI pelvis: for complex or large cysts prior to surgical planning. CECT chest/abdomen/pelvis: if malignancy is suspected — staging.

Conservative management (expectant): most functional cysts (simple, unilocular, below 5 cm, premenopausal) are managed conservatively with repeat ultrasound at 6-12 weeks — the majority resolve spontaneously. RCOG guidelines: simple unilocular cysts below 5 cm in premenopausal women — reassurance and 6-12 weekly repeat scan. Postmenopausal women with simple unilocular cysts below 5 cm and normal CA-125 — annual ultrasound follow-up (high resolution to resolve). Surgical management: laparoscopic ovarian cystectomy (removal of the cyst wall, preserving normal ovarian tissue) — preferred for benign-appearing symptomatic cysts, dermoids, endometriomas, and persistent cysts above 5-7 cm. Laparoscopic oophorectomy (removal of the whole ovary) — for postmenopausal women (where ovarian preservation is less important), large cysts with no normal remaining ovarian tissue, or high-risk features. Open (laparotomy) surgery: for large cysts, suspected malignancy (avoid spillage of malignant cells), or inability to complete laparoscopy. Ovarian torsion: emergency laparoscopic de-torsion — untwisting the ovary to restore blood supply (cystectomy at the same time if appropriate); oophorectomy if the ovary is non-viable. Suspected malignancy: full surgical staging by a gynaecological oncologist — total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, pelvic and para-aortic node sampling, peritoneal biopsies — followed by chemotherapy (carboplatin + paclitaxel for high-grade serous ovarian cancer).

Ovarian torsion (twisting of the ovary around its vascular pedicle — cuts off blood supply; surgical emergency requiring emergency laparoscopic de-torsion within hours to prevent permanent ovarian loss from ischaemic necrosis; most common with cysts larger than 5 cm and dermoid cysts — torsion risk doubles for every centimetre above 5 cm). Haemorrhagic rupture (corpus luteum haemorrhagic cysts — causes acute peritoneal irritation and blood loss; severe haemoperitoneum may cause haemodynamic instability requiring emergency laparoscopy for haemostasis). Malignant transformation (approximately 1 in 1,000 persistent ovarian cysts in reproductive-age women is malignant; significantly higher risk in postmenopausal women and BRCA1/2 mutation carriers — 44% and 12-20% lifetime ovarian cancer risk respectively). Fertility compromise from endometriomas (cystectomy destroys adjacent healthy ovarian cortex, reducing anti-Müllerian hormone and ovarian reserve — surgical timing and technique are critical; bilaterally or recurrently operated endometriomas may cause premature ovarian insufficiency).

Functional ovarian cysts cannot be reliably prevented. Combined oral contraceptive pills (OCPs) prevent functional cyst formation by suppressing ovulation — not used for this purpose alone but a consideration for women who require contraception and have recurrent functional cysts. Endometriomas: suppression of endometriosis with hormonal therapy (OCP, progestogen, GnRH analogues) slows progression but does not prevent endometrioma recurrence after cystectomy — postoperative hormonal therapy reduces recurrence. All ovarian cysts should have documented follow-up as per RCOG guidelines. Postmenopausal women with any ovarian cyst need at least one follow-up ultrasound and CA-125 to confirm stability or resolution. Women with BRCA1/2 mutations have significantly elevated lifetime ovarian cancer risk (44-46% for BRCA1; 12-20% for BRCA2) — risk-reducing bilateral salpingo-oophorectomy is recommended at age 35-40 (BRCA1) or 40-45 (BRCA2) after completion of family. BRCA1/2 gene testing is offered to women with significant personal or family history of ovarian or breast cancer.

Seek emergency care immediately for: sudden severe one-sided pelvic pain (possible ovarian torsion or cyst rupture — surgical emergency); sudden pain with dizziness, fainting, or signs of haemodynamic instability (haemoperitoneum from ruptured haemorrhagic cyst — may require surgery). See your GP or gynaecologist promptly for: new or worsening pelvic pain, a palpable pelvic mass, persistent bloating or abdominal distension (possible ovarian cancer — often presents with non-specific symptoms), urinary symptoms combined with pelvic mass, or post-menopausal pelvic symptoms (any new ovarian mass in a postmenopausal woman warrants urgent assessment). Women with known ovarian cysts should adhere to their scheduled follow-up ultrasound appointments — persistent or enlarging cysts require gynaecological review regardless of symptoms. Do not delay assessment of a new or changing ovarian cyst — while most are benign, early detection of the small minority that are malignant dramatically improves outcomes.