Introduction/Background In the last decades it has been speculated that endometriosis left untreated might lead to development of clear cell carcinoma (CCC) or endometrioid carcinoma (EC) of the ovary. In this paper we set up to investigate the strength of this association.

Methodology This is a single centre retrospective study looking at the incidence of endometriosis within the patients diagnosed with CCC and EC of the ovary over a 11 years period from 2011 to 2022. The paper and electronic records of 98 women treated within our centre in this period, for the aforementioned ovarian malignancies, were assessed.

Results From a total of 98 patients, primary debulking surgery was performed in 92 cases (93.9%) and in only 7 cases (7.1%) there was residual disease. CCC and EC were found in 31 cases (31.6%) and 67 cases (68.4%), respectively. Endometriosis was associated with 51.6% of CCC and 67.2% of EC. Overall, 62.2% (61) of all the patients in our series had a background of endometriosis.

Conclusion Almost two thirds of the patients in our series had concurrent endometriosis. As endometriosis is becoming a public health concern, aggressive treatment could reduce the risk of these women to develop an ovarian malignancy.

Disclosures No disclosure.