Primary adenocarcinoma of the ureter. Case report with immunohistochemical characterization.

Genuine adenocarcinomas of the ureter are rare tumors and have to be distinguished from other gland-forming malignancies arising from the transitional epithelium, due to the poor clinical outcome. The histopathological features of a tumor combined with intestinal metaplasia of the adjacent urothelium are described. The tumor has to be distinguished from transitional cell cancer with glandular metaplasia, muco-urothelial cancer, microcystic transitional cell cancer and transitional cell cancer with mucoid cytoplasmatic inclusions. Immunohistochemical analysis of the cancer shows positivity for carcinoembryonic antigen and a staining pattern characteristic for adenocarcinomas. The expression of keratin types 7 and 13, which is typically found in transitional cell carcinomas, is lost.