[Epidermoid carcinoma of the urinary tract. Immunohistochemical study].

Six patients diagnosed as having urothelial carcinoma with varying degrees of squamous features are described. Four had pure squamous carcinoma. Two had transitional cell carcinoma (1 with squamous areas and the other had carcinoma in situ). The histological analyses of specimens were performed using immunohistochemical techniques to detect epithelial markers with low molecular weight monoclonal antibodies to cytokeratin. The tests were positive for pure squamous carcinoma and transitional cell carcinoma with squamous areas, and were negative for all areas of transitional cell carcinoma. We underscore the importance of the squamous component in the prognosis of urothelial carcinomas as well as the usefulness of this type of markers, particularly low molecular weight antibodies to cytokeratin, in differentiating squamous areas.