The use of DNA typing to clarify the origin of metastatic carcinoma after renal transplantation. A clinical and medico-legal problem.

We present an unusual diagnostic problem in a transplant patient whose failed renal transplant was found to contain undifferentiated carcinoma. When the patient later developed metastatic renal carcinoma, he began legal proceedings against the hospital for the transmission of a tumour with his renal transplant. He subsequently died of carcinomatosis. Post-mortem examination revealed acquired renal cystic disease in his native kidneys with a 1-cm adenocarcinoma arising from the wall of one of the cysts. We used DNA typing to determine the origin of the metastatic tumour and resolve the medico-legal problem.