13 Brenner tumors were studied clinicomorphologically. The tumor nests are once again shown to arise in the benign variant due to the proliferation of the mucose-forming epithelium in the cysts with one-layer lining. Morphogenesis of the papillary structures in the border-line variety of the tumor is demonstrated. Three observations of the malignant Brenner tumors are described in which the relation to the preexisting nests of the benign analogue is proved. The hypothesis is proposed on the analogy of the morphogenetic mechanisms of the Brenner tumor structures formation with the processes of the proliferation of cervical channel cambial cells with their successive epidermization. It is suggested that the combination of mucinous cysts with Brenner tumor nests is one and the same process.