The goal of this clinical trial is to evaluate the safety and clinical outcomes of two-session catheter-directed sclerotherapy (CDS) with 96% ethanol in patients with endometrioma. The main question it aims to answer is:

• Is two-session CDS with 96% ethanol safe and effective for treating endometrioma?

Participants will:

• Receive the first session CDS for endometrioma
• Carry the catheter overnight and be monitored in the patient ward
• Receive the second session CDS the next day

Catheter-directed sclerotherapy has been reported as an effective treatment for endometrioma. However, whether the sclerosing agent should be retained inside the endometrioma was controversial. To increase the contact between the sclerosing agent and the endometrioma wall, two-session catheter-directed sclerotherapy using 96% ethanol was attempted, and safety and clinical outcomes were assessed in patients with endometrioma.

Inclusion Criteria:

• Aged ≥ 18 years
• Symptom manifestation as endometriosis (i.e., dysmenorrhea, dyspareunia, and lower abdominal or pelvic pain)
• Endometrioma ≥ 3 cm confirmed on ultrasound
• No evidence of solid lesions on ultrasound
• No suspected extraovarian endometriosis

Exclusion Criteria:

• History of gynecologic malignancy
• Active inflammation or infection
• Abnormal coagulation profile
• Loss to follow-up