An aggressive course of de novo ulcerative colitis after renal transplantation: colonic adenocarcinoma with choriocarcinomatous differentiation.

AIM: A rare case of colonic carcinoma arising in de novo ulcerative colitis after renal transplantation in a 42-year-old woman is reported. CASE: Clinically, the patient presented ulcerative colitis 8 years after renal transplantation, developed colonic cancer with liver metastasis 2 years later and died one month post operatively. Histologically, the removed tumor was composed of two distinctive elements consisting of adenocarcinoma and choriocarcinoma. The metastatic foci in the liver were composed exclusively of choriocarcinoma. Identification as choriocarcinoma was made on the basis of typical histological appearance, immunohistochemical demonstration of human chorionic gonadotropin (hCG) in the tumor cells and the high serum hCG level, unrelated to trophoblastic disease. In this report, pathogenesis is briefly discussed and clinical conditions are reviewed. CONCLUSION: In conclusion, the issue of de novo UC after organ transplantation is still a matter of debate. Further investigations are necessary to understand the tumorogenesis of colorectal cancer in de novo UC after renal transplantation,