Advances in sub-classification of ovarian carcinomas by cell type: an update

The histological classification of ovarian carcinomas has changed in recent decades. The five cell types that comprise the vast majority of cases are: high grade serous, low grade serous, endometrioid, clear cell and mucinous, and the criteria for distinguishing these types have evolved. Clinical, epidemiological, pathological and molecular evidence indicates that these cell types reflect different diseases. In particular, it has become clear that high and low grade serous carcinomas are sufficiently distinctive to warrant separate classification rather than different grades of a single type of carcinoma. High grade serous carcinoma causes the vast majority of ovarian cancer deaths and is the appropriate target for screening studies.