Endometrioid cystadenoma - deep ovarian endometriosis
Among all endometriosis lesions of female reproductive organs, ovarian endometrioma is the most discussed nosology. Since 2014, ovarian endometrioid cysts have been classified as benign tumors (WHO Classification of Tumours of Female Reproductive Organs, 4<sup>th</sup> edition). In 2021, the 11th revision of the International Classification of Diseases (ICD-11) was amended, according to which the term “endometrioid ovarian cyst” (from 2018 to 2021 - heading GA18.3 Ovarian endometriotic cyst, section GA18 Acquired abnormalities of ovary) is no longer used, and the clinical and morphological signs of these cysts are presented in the heading GA10.B5 Deep ovarian endometriosis. In 2020, WHO updated the histological classification of female genital tumors (Female Genital Tumours WHO Classification of Tumours, 5<sup>th</sup> Edition), in which the section “endometrioid tumors” is presented only with endometrioid cystadenoma and endometrioid adenofibroma without mentioning the endometrioid cyst, but in accordance with the ICD-11, endometrioid cystadenoma is coded as “GA10.B5 Deep ovarian endometriosis”. Thus, on the one hand, ovarian endometrioma is a neoplastic process and requires appropriate approaches when choosing treatment tactics, on the other hand, cystectomy for endometrioma is accompanied by a pronounced loss of ovarian reserve. A possible consensus in this problem seems to be a minimally invasive method in the treatment of patients with ovarian endometriomas - ethanol sclerotherapy with cytological examination of the aspirate obtained from the neoplasm. The effectiveness of sclerotherapy largely depends on the choice of postoperative hormonal therapy. Today, dienogest is considered to be the most effective “anti-endometrioid” progestogen. However, there is an erroneous opinion that ethinylestradiol neutralizes the antiproliferative effect of dienogest and stimulates the growth of endometriosis. On the contrary, ethinylestradiol enhances the inhibitory effect of progestogen on the growth of ovarian endometrioma cells.