The pattern of epithelial mucin secretion in normal, hyperplastic, and adenocarcinomatous endometrium

Stains for mucosubstances were performed on endometrial curetting material of normal and pathological endometrium. The study included normal proliferative and secretory endometrium, cystic and adenomatous hyperplasia, and endometrial adenocarcinoma. It was attempted to characterize the epithelial mucin in each of these conditions and to differentiate between them. The stains used were Alcian blue at pH 0.5 and 2.5; PAS with and without diastase digestion; and Toluidine blue. It was concluded that the Alcian blue stain at pH 2.5 was preferable for differentiating two groups: group one included benign conditions--normal endometrium, cystic hyperplasia, and adenomatous hyperplasia without atypia--in which the cytoplasm did not show any staining reaction. Group two included premalignant and malignant conditions, namely adenomatous hyperplasia with severe atypia and endometrial adenocarcinoma. In these conditions, definite staining of the cytoplasm was visible with Alcian blue at pH 2.5. The difference was statistically significant. In addition, strongly positive staining of the apical border was noted in both groups. Alcian blue at pH 0.5, PAS stain, and Toluidine blue were of no aid in differentiating the two groups. PAS stain resulted in positive apical and cytoplasmic staining in a large percentage of cases of all the different conditions. Toluidine blue did not show consistent staining of the cells. It was deduced that the cytoplasm of the premalignant and malignant group contained sulphated and nonsulphated acid mucopolysaccharides, as opposed to the benign conditions, in which the cytoplasm contained neutral mucopolysaccharides and glycogen. In each of the conditions acid and neutral mucopolysaccharides were present at the apical border. The finding of stainable cytoplasmic mucosubstances in endometrial adenocarcinoma is in contrast to what has been generally reported that such mucosubstances were characteristic of adenocarcinoma of endocervical origin only. Our study enabled us to differentiate endometrial adenomatous hyperplasia with severe atypia and adenocarcinoma from the more benign conditions by staining of cytoplasmic mucin with Alcian blue at pH 2.5.