Endometrioma

An endometrioma is an ovarian cyst that forms when endometriosis grows on or inside the ovary and fills with old menstrual blood. The dark brown fluid gives it the name "chocolate cyst." Endometriomas cause real damage.

They destroy healthy follicle tissue and lower ovarian reserve, the number of eggs left in the ovary. They also impair egg quality by creating an inflamed, iron-rich setting inside the ovary.¹

Medication alone does not remove an endometrioma. Suppressive medications shrink the cyst, but only while a woman keeps taking them. The cyst returns once they stop, and damage to the ovary builds up in the meantime.

Excision surgery is the standard endorsed in RRM. The procedure is a laparoscopic cystectomy. It removes the whole cyst wall. A 2024 Cochrane review compared excision with drainage and ablation.

With excision, the cyst returned far less often (odds ratio 0.17). Painful periods (dysmenorrhea) and pain during intercourse (dyspareunia) also returned less often.²

Timing also matters. A 2023 randomized trial (RCT) compared two times for cystectomy. One was the days immediately before a period (the late luteal phase). The other was shortly after a period begins (the early follicular phase).

Surgery immediately before a period better protected ovarian reserve.³ Even so, surgery itself can affect ovarian reserve, and this effect must be weighed. Cystectomy can shrink the pool of follicles, especially when cysts affect both ovaries or keep returning.

In RRM practice, clinicians plan endometrioma care around the stage of endometriosis, ovarian reserve tests, and fertility goals. Waiting without timely treatment is not a neutral choice. An untreated endometrioma keeps damaging nearby tissue. Every delay is a decision.