[Comparative morphological study of the peritoneal mesothelium and the germinal epithelium of the ovary. Histogenetic evidence for endometriosis].

The purpose of this study was to evaluate comparatively the morphology of germinal epithelium and of peritoneal mesothelial cells in women with and without endometriotic foci. In women without enometriotic foci, transmission electron microscopy revealed that plasma membranes of both cell types can form villous process, and that tonofilaments can be found in the cytoplasm; the microfibrils are well defined and may be arranged in perinuclear location or closely packed on the surface. Desmosomes are occasionally found in both cell types. In endometriotic foci, located either in the peritoneum or in the ovary, invaginations of the mesothelium into the underlying stroma are frequently observed, contiguous to well defined endometriotic tubules, or glandlike crypts. These structures are lined by a layer of cuboidal or high columnar cells. The cell membranes are well defined and run parallel to one another; small widening of the intercellular spaces is occasionally associated with a desmosome in the apical portion of the cell. These features may reflect Mullerian induction.