Ovarian tumors of borderline malignancy

Introduction The category of "ovarian tumors of borderline malignancy" was introduced by the World Health Organization (WHO) in 1971. By then it was recognized that there is a subset of relatively rare ovarian surface-epithelial tumors exhibiting pathomorphological features intermediate between clearly benign adenofibromas and clearly malignant adenocarcinomas, and that some of these intermediate tumors would behave in a malignant manner. The "borderline" terminology was meant to be a provisional one, until detailed studies would reveal definite criteria to classify these tumors as either benign or malignant. Now, 40 years later, we know a lot more about these tumors, there is a plethora of literature about them (very disproportionate to their actual incidence), and several attempts have been made to eliminate the unfortunate "B" word. In fact, the latest edition of one of the major gynecologic pathology textbooks declares the "serous borderline" category as no longer needed [1]. However, no general consensus about the terminology has been achieved, and these tumors continue to cause considerable controversy among the experts. "Borderline" is still an accepted, if not the preferred term by the majority of pathologists and gynecologic oncologists.