Endometriosis affects one in seven women and is more common in certain groups, affecting 50% of women with chronic pelvic pain, 40% of women with subfertility and 25% of transgender men. Symptoms include pelvic pain, dysmenorrhoea, dyschezia, dyspareunia, fatigue and subfertility.
Endometriomas, commonly called chocolate cysts, are collections of endometriosis within the ovary. Endometriomas often occur concurrently with deep infiltrating endometriosis (D.I.E), with over 60% of those with an endometrioma having D.I.E.
While most endometriomas are benign, larger endometriomas are more likely to be malignant, with 0.8% of endometriomas larger than 4cm being malignant. Size of the endometrioma should be used to risk-stratify patients as other markers, such as serum Ca-125, are not a useful measure to distinguish cases of ovarian cancer as their level is often elevated with endometriosis.
Treatment of endometriomas
The correct treatment depends on the symptoms, size of the cyst and the patient’s preference:
1. Endometriomas <4cm and asymptomatic
- Treatment is not required
- Surveillance of the endometrioma is recommended. Reasonable surveillance involves ultrasound at 6 and 12 months, then yearly if stable in size and appearance
- Surgery may be considered for those at higher risk of ovarian cancer, after counselling
2. Endometriomas <4cm size with pain
- Treatment options should include non-hormonal, hormonal and surgical
- Non-hormonal treatment: NSAIDs have the best evidence for pain management
- Hormonal treatment: The COCP or progesterone-only medications such as progesterone-only contraceptive pills, depot injections or IUD coil. (The progesterone IUD is unlikely to shrink an endometrioma, however, it can provide symptom relief from other endometriosis)
- GnRH analogues can treat pain associated with endometriomas but given their side effects, should only be prescribed long term in a multidisciplinary setting by a gynaecologist who specialises in endometriosis management
- Surgical management should be offered as a treatment option to all patients who have persistent pain despite medical treatment or to those who prefer surgery as first-line treatment
3. Endometriomas >4cm
- Surgical management is recommended due to the higher chance of malignancy with endometriomas of this size.
Surgical management of endometriomas
- Drainage of an endometrioma alone should not be performed for symptom management, as there is a 100% chance of recurrence
- 60% of patients with an endometrioma will have D.I.E, therefore a D.I.E Ultrasound should be performed as part of a pre-operative work-up for all patients with an endometrioma who are planning to have surgery
- If imaging confirms D.I.E, surgery is of a high level of complexity and should be undertaken by a specialist with formalised training in advanced laparoscopic surgery
- Patients should be advised pre-operatively on the pain outcomes following surgery: 80% will experience a significant improvement in pain following surgery, just under 20% will notice no change to their pain and 1-2% will experience a worsening of pain following surgery
- Treatment of an endometrioma should be via laparoscopic ovarian cystectomy (removal of the cyst wall) as this has been associated with a lower chance of recurrence and a smaller decline in ovarian reserve compared to ablation of ovarian tissue. Other equally effective options are ovarian sclerotherapy.
Endometriomas and fertility
Surgical excision of endometriomas has been shown to improve spontaneous pregnancy rates in those with subfertility and should be offered as a management option. Surgery for endometriomas has no effect on IVF/ICSI outcome and therefore should only be offered to this group of patients for pain management or to exclude malignancy (i.e. the endometrioma is >4cm)
Any patient who has surgery for an endometrioma should be offered hormonal suppression post-operatively to reduce the recurrence rate as two or more surgeries on an ovary for an endometrioma has been shown to be a significant risk factor for unsuccessful fertility treatment.
Key messages
- 60% of those with endometriomas have concurrent deep infiltrating endometriosis. All patients with an endometrioma having surgery need a pre-operative D.I.E Ultrasound
- If D.I.E is found on imaging, surgery is of a high level of complexity, however a negative D.I.E scan does not completely exclude the presence of D.I.E or of significant pelvic adhesions
- Endometriomas larger than 4cm should be surgically resected due to the higher risk of malignancy.
Author competing interests – nil