[Ultrastructure of the ectopic endometrial glandular epithelium in five cases of adenomyosis--with particular reference to the normal proliferative endometrium and endometrial adenocarcinoma].

Although we encounter endometriosis not infrequently, the exact nature of this entity has not yet been determined. In order to study the morphogenesis of this disease, we chose the adenomyotic glandular epithelium as distinct ectopic glands and examined them in the electronmicroscope, comparing them with the proliferative phase of the endometrium and the uterine body adenocarcinoma. Five cases were selected from 76 histologically proven cases of adenomyosis at our University. Epon blocks were ultrasectioned with a Porter MT II microtome, stained with uranium acetate and lead, and observed in a JEM 100 C electronmicroscope. The characteristics of adenomyotic glandular epithelium compared to the normal proliferative endometrium were: 1) expanded smooth nuclear membrane with scattered fine chromatin and zero to one irregularly surfaced nucleoli, 2) in cytoplasm, rough ER and free ribosomes are distinct, mitochondria are round to oval in shape with moderate irregularity, and microfibrillar structures and interdigitations are present in moderate amounts. Although there are few similarities to endometrial cancer, these findings would suggest that adenomyosis may be an intermediate between the normal proliferative endometrium and endometrial cancer.