[Ultrastructural characteristics of cervical dysplasia and carcinoma in situ].

Some ultrastructural features of cervical dysplasia and carcinoma in situ were revealed by electron microscopic studies of cervix specimens from 24 women. Both types of preinvasive disorders are characterized by alterations in the distribution of nuclear chromatin, the outline of the nuclear membrane, the amount of cytoplasmic organelles, and the mode of cellular attachment. Unlike dysplasia, a great variety of morphological patterns was found in carcinoma in situ which could be subdivided into squamous and reserve cell types. In carcinoma in situ, there was no increase in differentiation of cells and the cell surface up to the outermost layers. The basal membrane was altered only in carcinoma in situ epithelium. The ability of the epithelial cell processes to penetrate through the altered basal membrane and to invade the underlying stroma may be the evidence of the malignancy of cells in carcinoma in situ but not in dysplasia where the basal membrane was unaltered.