Endometriosis is a benign, chronic, and often recurrent gynecological disease affecting approximately 10% of women of reproductive age. Among the different manifestations of the disease, ovarian endometrioma represents one of the most common forms, occurring in up to 50% of affected patients. Endometriomas may cause progressive damage to ovarian tissue through both mechanical effects and direct toxic effects related to the inflammatory and oxidative content of the cyst, ultimately leading to a reduction in ovarian reserve.

When medical treatment is insufficient or not indicated, surgery represents a therapeutic option. The aim of surgery is to remove the cyst while minimizing the risk of recurrence and preserving as much healthy ovarian tissue as possible. Currently, the most widely used surgical technique is laparoscopic cystectomy performed by stripping the cyst capsule. However, this procedure may result in the inadvertent removal of healthy ovarian tissue and a consequent reduction in ovarian reserve.

In recent years, ablative surgical techniques have been developed with the aim of reducing damage to the ovarian parenchyma. Among these, Argon Plasma Coagulation (APC) is a technique that uses a high-energy argon plasma jet to vaporize and coagulate superficial tissues. From a histological perspective, APC induces limited-depth tissue necrosis, generally confined to the cyst capsule, potentially reducing the risk of damage to the underlying ovarian tissue. In addition, this technology may offer practical and economic advantages.

Several studies suggest that ablative techniques may have a lower impact on ovarian reserve compared with cystectomy, as assessed by antral follicle count and serum anti-Müllerian hormone (AMH) levels, a reliable biomarker of ovarian reserve. However, the available evidence mainly derives from observational studies or studies using ablative technologies different from the one investigated in the present study. Furthermore, the systematic use of ablative techniques remains controversial in clinical practice, partly because of the potential risk of recurrence associated with residual endometriotic tissue.

To date, no randomized clinical trials have directly compared the impact of APC versus cystectomy on ovarian reserve in patients with ovarian endometrioma. Moreover, data are lacking regarding recurrence risk, post-treatment ovarian ultrasound characteristics following APC ablation, and the histological effects of this technique on endometriotic cysts.

In light of these considerations, the present randomized clinical trial aims to compare the effect of cystectomy and Argon Plasma Coagulation ablation on the preservation of ovarian reserve in patients undergoing surgical treatment for ovarian endometrioma, while also evaluating ultrasound outcomes and recurrence risk during follow-up.

Inclusion Criteria:

• Symptomatic patients (pain and/or infertility) affected by ovarian endometriomas (unilateral or bilateral).
• Age between 18 and 40 years.
• Ultrasound diagnosis of one or more mono- or bilateral endometriotic cysts, with a maximum overall diameter (per ovary) ≤ 80 mm and at least one cyst diameter ≥ 20 mm.
• Use of hormonal therapy for at least 1 month prior to surgery.
• Willingness to undergo follow-up at 40-60 days and 12 months, according to clinical practice.
• Willingness to receive postoperative hormonal therapy, according to clinical practice, to minimize the risk of recurrence.
• Written informed consent obtained.

Exclusion Criteria:

• History of unilateral ovariectomy/adnexectomy or hysterectomy.
• Ultrasound evidence of other non-endometriotic ovarian cysts requiring surgical removal.
• Atypical endometrioma or ultrasound suspicion of malignancy.
• Previous surgery on one or both ovaries within 12 months prior to surgery.
• Known or suspected active oncological disease.
• Inability to undergo transvaginal ultrasound examination (patients with intact hymen).