Value of immunohistochemical demonstration of several epithelial markers in hyperplastic and neoplastic endometrium

The distribution of prekeratin, vimentin, epithelial membrane antigen (EMA), and secretory component (SC) was demonstrated immunohistochemically in 31 patients with adenomatous hyperplasia (AH), 12 patients with atypical adenomatous hyperplasia (AAH), and 39 patients with endometrial carcinoma. Prekeratin was presented in 94% of AHs, 92% of AAHs, and 87% of adenocarcinomas. Vimentin was detected in 68% of AHs, 50% of AAHs, and 37% of adenocarcinomas, showing decreased expression as the lesion progressed to malignancy (P less than 0.05). EMA was detected in 26% of AHs, 67% of AAHs, and 95% of adenocarcinomas (P less than 0.001). SC demonstrated focal and weak expression in 29% of AHs, but showed increased staining intensity in 67% of adenocarcinomas (P less than 0.01). Well-differentiated tumors expressed SC better than poorly differentiated tumors (P less than 0.01). All markers showed a heterogeneous staining pattern and, for a given histologic hyperplastic or neoplastic state, corresponded to several phenotypes. In conclusion, prekeratin seems to be a good marker for epithelial differentiation in hyperplastic endometrium, and EMA is a good marker in neoplastic endometrium. In hyperplastic lesions, the loss of vimentin expression in the absence of secretory changes gives rise to suspicions regarding their benign process. Also, EMA can help in distinguishing between hyperplastic and neoplastic states, while detection of SC may be of help in more precise grading of endometrial carcinoma.