Isn't "epithelial carcinoma" a tautological term? Are there non-epithelial carcinomas?

Question

From "Bevacizumab combined with platinum–taxane chemotherapy as first-line treatment for advanced ovarian cancer: a prospective observational study of safety and efficacy in Japanese patients (JGOG3022 trial)":

In Japan, it is estimated that 9804 new patients develop ovarian cancer every year and the estimated annual number of deaths from this cancer is 4758, with its outcome being the worst among female genital tract cancers. The underlying reasons are that about 90% of ovarian cancer is epithelial carcinoma, with approximately 50% of epithelial ovarian cancers being Stage III or Stage IV advanced disease at diagnosis (2).

Is "epithelial carcinoma" a redundant phrase, or am I missing something? I thought that the word carcinoma meant "epithelial cancer".

Answer 1

You are correct that carcinoma refers to types of cancer arising from epithelial tissue.

Definition of carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs.

This includes tissues that line both the inner and outer surfaces of the body and that arise from cells originating in the endodermal, mesodermal or ectodermal germ layer during embryogenesis. Source: Wikipedia.

This also includes glandular tissue, even if this tissue is within an organ, as glands contain many ducts lined with secretory cells and this is also epithelium.

However, in the specific case of epithelial ovarian cancer, it refers to cancers arising on the surface of the ovary (the germinal epithelium), rather than the tissues within, as there is technically epithelial tissue inside as well. Source: Cancer Research UK.