Endometrioma

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated July 27, 2026

An endometrioma is an ovarian cyst formed when endometriotic tissue implants on or within the ovary and fills with old menstrual blood, producing the characteristic dark-brown "chocolate cyst" appearance. Endometriomas are not benign bystanders. They destroy healthy follicular tissue, reduce ovarian reserve, and impair oocyte quality by creating an inflammatory, iron-rich environment within the ovary itself.¹

Medical management does not resolve endometriomas. Suppressive medications shrink the cyst while treatment continues, but the lesion returns after discontinuation and ovarian damage accrues in the interim. Excision surgery is the standard endorsed in RRM: laparoscopic cystectomy with complete removal of the cyst wall. A 2024 Cochrane review found that excision reduces endometrioma recurrence compared with drainage and ablation (OR 0.17), and also reduces recurrent dysmenorrhea and dyspareunia.² A 2023 RCT found that timing cystectomy to the late luteal phase, rather than the early follicular phase, better preserves ovarian reserve after surgery.³

The ovarian reserve impact of surgery itself must be weighed. Cystectomy can reduce the follicular pool, particularly in bilateral or recurrent cases. This makes surgical decision-making in reproductive-age women consequential. In RRM practice, clinicians evaluate endometrioma management in the context of endometriosis stage, reserve markers, and fertility goals. Surveillance without timely treatment is not neutral: untreated endometriomas carry their own progressive damage to surrounding tissue. Every delay is a decision.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.