CT OF HILAR CHOLANGIOCARCINOMA - LATE CONTRAST ENHANCEMENT IN 6 PATIENTS

Hilar cholangiocarcinoma usually appears on CT scans as a low-density or isodense mass that abruptly obstructs converging dilated bile ducts. In four of six patients with histopathologically proved hilar cholangiocarcinoma who had late enhanced CT 8-15 min after dynamic CT, the lesion was seen as a high-density mass instead of the low-density lesion seen earlier on unenhanced and dynamic CT scans. The other two patients had ring enhancement with evidence of a thickened wall of the bile duct both on early and late enhanced CT scans. In the first four patients, carcinoma invaded the neighboring hepatic parenchyma and produced a mass, whereas in the last two, carcinoma was localized in the wall of the bile duct. Histopathologically, all lesions consisted of adenocarcinoma associated with a dense fibrotic tissue. As late enhanced CT shows hilar cholangiocarcinoma as a high-density mass, the exact location of the tumor and its relation to neighboring vessels can be determined, especially in relatively small tumors, and differentiation from sclerosing cholangitis is possible.