Definition
Probably better referred to simply as "serous carcinoma" (a papillary architecture may be inconspicuous), this is a carcinoma that most commonly arises in the ovary. Less common sites of origin include the endometrium, the cervix uteri and fallopian tube (the last of these sites being particularly represented among women with germline BRCA mutations). A small number of cases occur in the peritoneum with no/minimal involvement of the female genital organs, and these are referred to as primary peritoneal serous carcinoma.

The large majority of these tumours are high grade (agressive) malignancies. A small number of cases are of low-grade type. There is significant recent evidence that these latter tumours are histogenetically distinct.


Source

Source: The National Cancer Institute (NCI)