[Early forms of ovarian cancer--are there borderline tumors?].

The early development of ovarian cancer remains unclear. Inclusion cysts or papillary excrescences of the germinal epithelium probably play a role. After a preinvasive stage, these lesions undergo secondary malignant transformation. The issue of borderline tumors is made complicated by diagnostic imprecision and by the fact that the peritoneal epithelium can develop autonomous tumors that look like metastases.