[Scanning electron microscopic study on pathogenesis of peritoneal endometriosis].

To investigate the pathogenesis of peritoneal endometriosis, the morphology of peritoneal endometriosis was studied by scanning electron microscopy (SEM) and light microscopy (LM). After taking biopsies from peritoneal lesions which were suspected of being endometriosis during laparoscopy, the peritoneal surfaces of specimens were studied by SEM. Subsequently, for histologic examination of SEM findings, some SEM blocks were embedded in Epon, and LM observation of sections of Epon-embedded SEM blocks was done. In SEM observations, no ciliated cells were observed on the surface of peritoneal endometriotic lesions, but domed cells were observed in 17 of 44 specimens and surface configurations were cobblestonelike in appearance. In combined observation with SEM and LM, they were suspected of being epithelioid-changed mesothelial cells. On the cellular surface, folds, hollows and apocrine secretion (one SEM block) were observed. Furthermore, the peritoneal surface structure which covered these epithelioid-changed mesothelial cells was not always flat, but sometimes invaginations and glandular opening-like structures were observed on them. These changes in mesothelial cells and the peritoneal architecture may reflect the process of transdifferentiation to müllerian epithelium and support the metaplastic theory of the pathogenesis of endometriosis.