Ultrastructural and morphometric study of diethylstilbestrol-associated lesions diagnosed as cervical intraepithelial neoplasia III.

Investigations were carried out to characterize diethylstilbestrol (DES)-associated squamous lesions and to assess their biological significance. Five DES-associated cervical lesions displayed architectural features which were diagnosed as cervical intraepithelial neoplasia (CIN) III, such as full-thickness replacement by atypical squamous cells with vertical orientation and absence of normal polarity. Electron microscopic examination revealed only one of the five to be consistent with the generally recognized ultrastructural picture of non-DES CIN III. In the remaining four lesions, the moderate-to-large numbers of tonofibrils and well-developed desmosomes distinguished them from the true CIN III lesions. Morphometric studies indicate the five DES-associated lesions in this study as a group to be significantly different from normal squamous epithelium, from maturing metaplasia, and from non-DES-related CIN III in the parameters of differentiation studied. Their intermediary position between maturing metaplasia and non-DES CIN III suggests that they are more differentiated than CIN III and less differentiated than maturing metaplasia. Nuclear area measurements indicate the increased nuclear-cytoplasmic ratio observed in the DES-associated CIN III lesions of this study is due to a decrease in cytoplasmic volume, as opposed to an increased nuclear size.