Scanning electron microscopy of the endometrial cell surface in postmenopausal women receiving oestrogen therapy.

The surface ultrastructure of normal and abnormal endometrial cells from patients receiving oestrogen therapy for the climacteric syndrome was studied by scanning electron microscopy. Patients with endometrial pathology were treated with oral progestogens. Excessive oestrogen stimulation caused proliferation of cilia and microvilli. Cystic hyperplasia was characterised by a proliferation of cilia until they covered more than one-third of the surface area of the endometrium; further proliferation occurred in cases of adenomatous hyperplasia when the surface was almost completely covered with cilia. Cell morphology remained apparently normal until atypical hyperplasia, when occasional cells appeared large and irregular, or adenocarcinoma occurred, when the surface cells appeared large, pleomorphic and sometimes wrinkled, being mostly devoid of cilia. Although cystic hyperplasia was converted to a normal histological picture of atrophic or pseudo-decidual endometrium by courses of progestogen, the deciliated endometrial cells showed persisting abnormal ultrastructural characteristics.