Is ovarian cystectomy for atypical ovarian endometrioma safe?: A single center study

Ovarian atypical endometriosis (AE) is a premalignant lesion, and its potential to progress to endometriosis-associated ovarian cancer emphasizes its significance. However, the true risk of malignancy in AE remains unclear. Therefore, this study aimed to investigate the clinical outcomes of ovarian AE after ovarian cystectomy. We retrospectively reviewed the medical records and histopathological reports of 41 patients who had been diagnosed with ovarian AE between January 2011 and April 2020. We reviewed age, obstetric history, age at menarche, preoperative CA 125 level, C-reactive protein level, erythrocyte sedimentation rate, endometriosis stage, mean follow-up duration, postoperative hormonal therapy, and prognosis, including recurrence of endometriosis and malignant transformation. Among 41 patients with pathologically diagnosed ovarian AE, 26 were followed up after cystectomy only. The average follow-up period was 58.27 ± 33.22 months in cystectomy only patients. The mean age of the patients with cystectomy only versus that of patients with endometriosis-associated ovarian carcinoma was 32.73 ± 6.10 versus 48.29 ± 4.35 (P < .01) years. The preoperative CA 125 level was 115.63 ± 219.06 versus 225.75 ± 163.39 (P < .051) U/mL. Patients with endometriosis-associated ovarian carcinoma or other diseases and those who underwent oophorectomy were excluded. After surgery, hormone therapy was administered to 22 of 26 patients, and the remaining 4 patients were followed up without additional treatment. Endometriosis recurrence occurred in 5 patients, 1 of whom underwent second-line laparoscopic ovarian cystectomy. However, no malignant transformations were observed. Ovarian AE has a low possibility of malignant transformation. Conservative treatment is recommended after appropriate ovarian cystectomy, such as enucleation.