ULTRASTRUCTURAL-STUDY OF THE NUCLEI OF NORMAL, DYSPLASTIC, AND CARCINOMATOUS EPITHELIAL-CELLS OF THE HUMAN CERVIX UTERI

The nuclei of epithelial cells of the uterine cervix of normal women a nd of patients with Various degrees of dysplasia, carcinoma in situ, a nd invasive carcinoma were studied by means of electron microscopy. Nu clear ribonucleoprotein components and chromatin were contrasted using preferential methods for RNA and DNA. Changes in the distribution of the extranucleolar ribonucleoprotein-containing structures were found, ranging from low-grade dysplastic lesions to invasive carcinoma. Comp ared with normal epithelial cells, dysplastic and neoplastic cells pos sess more nuclear bodies, as well as deep invaginations of the nuclear envelope and lobulations. Morphometric parameters estimated were nucl ear volume, numerical density of perichromatin granules (PCG), and fra ction of nuclear volume occupied by compact chromatin. The pattern of values of these parameters in the cell layers of normal cervical epith elium was disrupted in all the lesions. These data suggest that the pr ocesses studied induce early alterations in transcription and processi ng and/or exportation of mRNA to the cytoplasm. Two populations of cel ls were found in invasive carcinomas, one with large nuclei, sparse co mpact chromatin, and few PCG, end the other with small nuclei, abundan t compact chromatin, and numerous PCG. Their morphologic features indi cate that the former population is composed of relatively undifferenti ated cells, while the latter is made up of well-differentiated cells w hich could be neoplastic or entrapped normal cells.