Endometrial cytology in postmenopausal hormone replacement therapy

Endometrial changes is postmenopausal hormone replacement therapy (HRT) were studied by comparing cytological and histological findings. Cytological and histological examinations were conducted on 138 benign cases and 26 abnormal cases, including 24 cases with disordered proliferative phase (DOP) and 2 cases with simple endometrial hyperplasia (SEH), for a total of 164 cases. Hormones were administered as follows: 1) single cyclic administration of estrogen only (Single-HRT) for 31 cases, 2) cyclic administration of estrogen and progestin (Cyclic-HRT) for 105 cases, and 3) continuous administration of estrogen and progestin (Continuous-HRT) for 28 cases. All of the 164 cases were studied cytologically as to shape, appearance, nuclear number on maximum diameter, and so on. The benign cases in each mode of administration as described above revealed the following: 1) Single-HRT, atrophy or the proliferative phase was noted histologically, and the copresence of the endometrial epithelium and the ciliated cell metaplasia was observed cytologically; 2) Cyclic-HRT, the first half of the administration term was of the proliferative phase histologically, and the linear and long glands were seen cytologically. In the latter half of the administration term the secretory phase was noted histologically and the curved/linear glands with subnuclear vacuolization were observed cytologically; and 3) Continuous-HRT, atrophy was noted histologically, and fewer glands and atrophic cells on the endometrial epithelium with wrinkles mixed therein were seen cytologically. On the other hand, cytological examinations of the abnormal cases revealed a mean average of 35 nuclei on the maximum diameter of the gland, protrusion and/or ramification of the glands, densely clustered glands, and back-to-back glands without fusion, as well as irregularly dilated tortuous glands in SEH. These abnormal findings were considered useful for early detection of endometrial disorders in the hormone replacement therapy by cytodiagnosis.