Case Series and a Literature Review: Two Ovarian Clear Cell Carcinoma Cases with Recurrent Endometriosis

Endometriosis-associated ovarian cancer (EAOC) is rare, occurring approximately in 1% of women with ovarian endometriosis. The main histological types are endometrioid adenocarcinoma and clear cell carcinoma (CCC), with the latter being the least common.

In our hospital, we recently summarized two patients with ovarian clear cell carcinoma with similar characteristics. They all had endometriosis for a long time and had undergone ovarian cyst removal due to a chocolate cyst. Unfortunately, the cyst recurred after surgery, and the histological diagnosis was clear cell carcinoma. In case 1, the expression of P53 was found in the tumor by regular examination, and the stage was IIB. In Case 2, we found it in intraoperative freezing; the stage was IA. Case 1 has been treated with the TP regimen six times, and the survival period has reached one year. Case 2 had a survival period of 6 years after completing six TP regimen treatments. Clinicians should pay attention to patients with a long history of endometriosis and postoperative recurrence of ovarian cysts accompanied by serum CA-125 of more than 200U/mL. Imaging examination has a good prospect in diagnosing malignant transformation of endometriosis, especially PET-CT.

This case report highlights the risk factors related to the formation of ovarian clear cell carcinoma and suggests that the follow-up of patients with ovarian endometriosis is essential because of its recurrence characteristics. Radical surgery and postoperative platinum-containing chemotherapy are the primary treatment methods at present.