Cholangiocarcinoma occurring after childhood radiotherapy for Wilm's tumor.

Some patients have been given radioactive thorium dioxide as an intravascular contrast agent. Retained particles of thorium in the liver have chronically irradiated hepatic tissues and sometimes caused cholangiocarcinomas and other malignancies. We studied a young woman who developed cholangiocarcinoma in liver tissue which was included in the field of external beam therapy given for Wilm's tumor some twenty years earlier. Radiation-induced cholangiocarcinoma may not necessarily require chronic exposure to ionizing radiation.