[Classification of ovarian tumors based on embryogenesis]

This paper studies gonadal differentiation into the ovary from the earliest interaction between germ cells and somatic cells in the developing urogenital ridge up to the formation of primordial follicles. Granulosa cells appear to be derived from the breaking down of the cordlike arrangement of epithelial cells resulting from proliferation of surface coelomic mesothelium. Thecal cells arise from mesenchymal progenitors cells in the ovarian stroma. Based on the findings of embryology and biology, the authors then propose a classification of ovarian tumors by rearranging the WHO classification.