Complex Ovarian Cyst

A complex ovarian cyst is an ovarian cyst with septa, solid areas, papillary projections, thick walls, or internal echoes on ultrasound.

• Causes include haemorrhagic cyst, endometrioma, dermoid cyst, cystadenoma, tubo-ovarian abscess and ovarian cancer.
• Some are benign and others are malignant, so risk assessment is needed.
• Assessment uses ultrasound features, CA-125 and menopausal status.

Pelvic pain, bloating, early satiety, urinary frequency, abdominal enlargement, or no symptoms.

• A fixed or irregular adnexal mass, ascites or nodularity in malignancy.
• Differential diagnosis: endometrioma, mature teratoma, serous or mucinous cystadenoma, ovarian cancer, tubo-ovarian abscess, pedunculated fibroid, ectopic pregnancy, haemorrhagic cyst.
• Complications: rupture, torsion, infection, malignant spread and ascites.

Diagnosis is by Doppler ultrasound with a malignancy risk index, supported by tumour markers and cross-sectional imaging.

• Transvaginal ultrasound with colour Doppler, recording size, septa, solid parts, papillae, ascites and flow.
• Risk of malignancy index (ultrasound score times menopausal score times CA-125); an index of 200 or more needs gynaecological oncology referral.
• CA-125; in women under 40 or with solid masses add alpha-fetoprotein, human chorionic gonadotrophin and lactate dehydrogenase.
• MRI or CT scan of the pelvis and abdomen for staging or characterisation; chest X-ray.
• Histology after removal; avoid biopsy of a suspected cancer through the skin.

Assess the risk of malignancy first, then remove the cyst intact or refer for cancer surgery.

• Supportive: counselling on diagnosis and need for surgery; optimise anaemia and nutrition; refer early.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) and ibuprofen 400 mg oral 8-hourly with food (maximum 1.2 g in 24 hours) for pain. Anaemia: ferrous sulphate 200 mg oral 8-hourly. Infected cyst or abscess: ceftriaxone 1 g IV daily plus metronidazole 500 mg IV 8-hourly.
• Procedures: laparoscopic cystectomy or oophorectomy for low-risk lesions, with the specimen removed intact in a retrieval bag; laparotomy with frozen section, hysterectomy, bilateral salpingo-oophorectomy, omentectomy and staging for suspected malignancy, by a gynaecological oncologist. Observation with repeat ultrasound at 6 to 12 weeks for probable haemorrhagic cysts.
• Special groups: in pregnancy defer surgery to the second trimester unless torsion, rupture or suspected cancer. In girls and women under 40 who want fertility, preserve the uterus and the other ovary where possible.
• Red flags: ascites, solid areas with flow, CA-125 above 35 units/mL in postmenopausal women, rapid growth, weight loss, pleural effusion.
• Follow-up: histology review at 2 weeks; oncology plan; yearly review after benign surgery.