Ultrasound study of natural progression of ovarian endometrioma.

Objective: To determine the natural progression of ovarian endometrioma in women who are managed expectantly.

Methods: This was a retrospective cohort study of 83 women with evidence of ovarian endometrioma who were managed expectantly between April 2007 and May 2022. The study was conducted in the Department of Women's Health, University College London Hospitals and The Gynecology Ultrasound Centre, London, UK. We searched our ultrasound clinic databases to identify women aged 18 years or older with evidence of ovarian endometrioma who were managed expectantly for ≥ 6 months. All women attended for a minimum of two ultrasound scans performed by a single expert ultrasound operator. In addition to patient demographics, we recorded the number, mean diameter and location of each cyst. The cyst growth rate was expressed as annual change in the mean diameter.

Results: A total of 1922 women who attended our gynecology clinic during the study period were found to have evidence of moderate or severe endometriosis on pelvic ultrasound examination. Of those, 83 women had evidence of ovarian endometrioma and were managed expectantly. The median age of women was 39 (range, 26-51) years at the initial visit. Each woman had at least two ultrasound scans performed by a single expert operator at a minimum interval of ≥ 6 months. Of 83 women diagnosed with endometrioma, 50 (60% (95% CI, 49-71%)) had a single cyst and the remainder had multiple cysts. The median number of endometriomas per patient was 1 (range, 1-5) and the median follow-up time was 634 (range, 187-2984) days. A total of 39/83 (47% (95% CI, 36-58%)) women experienced an overall reduction in size of cysts, in 18/83 (22% (95% CI, 13-32%)) the cysts increased in size and in 26/83 (31% (95% CI, 22-42%)) women, no meaningful change in size was observed. The median change in mean cyst diameter per woman during the study period was -2.7 (range, -57.7 to 39.3) mm, with a median annual regression rate of -1.7 (range, -24.6 to 42.0) mm/year/woman. Overall, when compared with the initial visit, cysts were significantly smaller at follow-up (median diameter, 22.3 (range, 6.7-77.0) mm vs 18.5 (range, 5.0-72.0) mm; P = 0.009). We did not identify any clinical characteristics that could reliably predict the chance of endometrioma progression.

Conclusions: In the majority of women with an ultrasound diagnosis of ovarian endometrioma, the cysts do not increase in size significantly over time and they could be managed expectantly. This evidence may help clinicians when counseling asymptomatic or minimally symptomatic women about management of ovarian endometrioma. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.