Clear cell papillary carcinoma of the liver: an unusual variant of peripheral cholangiocarcinoma.

Cholangiocarcinomas may be extrahepatic or intrahepatic; the latter are further divided into hilar and peripheral types. Peripheral cholangiocarcinomas often resemble adenocarcinomas arising in other organs. Although clear cell changes may occur in hepatocellular carcinoma and extrahepatic cholangiocarcinoma, peripheral cholangiocarcinomas with clear cell change are rare. In such cases, an extrahepatic primary carcinoma must be excluded. We present a patient with a large, clear cell papillary carcinoma in the liver. Extensive workup of the patient for other possible primary sites including kidneys, adrenals, thyroid, prostate, or urinary bladder failed to indicate any other neoplasm. The patient is alive without evidence of disease 30 months after complete resection. The histological, immunohistochemical, and electron microscopic results were most consistent with a neoplasm in the cholangiocarcinoma family. To the best of our knowledge, a clear cell papillary peripheral cholangio carcinoma has not been described previously. This neoplasm may be related to the recently described clear cell carcinomas of the gallbladder and extrahepatic bile ducts.