Ovarian borderline tumours: a review with comparison of serous and mucinous types

Ovarian borderline tumours are relatively uncommon but not rare neoplasms. A large majority are of serous or mucinous type with other morphological variants being much more uncommon. In this review, the clinicopathological features of ovarian borderline tumours are discussed, concentrating on serous and mucinous neoplasms. Other morphological types are briefly discussed. A comparison is made between serous and mucinous borderline tumours which exhibit marked differences with regards to incidence of bilaterality, surface involvement, extraovarian spread, lymph node involvement, risk of malignant progression and prognosis. It has been suggested that the category of borderline tumour be abandoned for both serous and mucinous neoplasms but this terminology is useful for both types but for different reasons, namely the significant risk of extraovarian disease in serous borderline tumours and the large size and heterogeneity of mucinous borderline tumours which can result in an invasive focus being undetected by the pathologist.