Ovarian clear-cell carcinoma, or clear-cell carcinoma of the ovary, also called ovarian clear-cell adenocarcinoma, is one of several subtypes of ovarian carcinoma ¨C a subtype of epithelial ovarian cancer, in contrast to non-epithelial cancers. According to research, most ovarian cancers start at the epithelial layer which is the lining of the ovary. Within this epithelial group ovarian clear-cell carcinoma makes up 5¨C10%. It was recognized as a separate category of ovarian cancer by the World Health Organization in 1973. Its incidence rate differs across various ethnic groups. Reports from the United States show that the highest rates are among Asians with 11.1% versus whites with 4.8% and blacks at 3.1%. These numbers are consistent with the finding that although clear-cell carcinomas are rare in Western countries they are much more common in parts of Asia.

Reference
Wiki: Ovarian mucinous carcinoma