Surface epithelium of the developing ovary. Possible correlation with ovarian neoplasia.

The surface epithelium of the fetal ovary undergoes diffuse proliferation during the fourth and fifth months of gestation, after which it reverts to a single layer separated from the developing cortex by a tunica albuginea. The proliferation is associated with marked nuclear irregularity and pleomorphism similar to that seen in surface epithelial neoplasms. The epithelial changes occur during the same time period that interstitial cells with ultrastructural and histochemical properties of steroid-secreting tissue appear in the ovarian stroma. The possible role of steroid hormones in stimulating surface epithelial proliferation is discussed.