Primary clear cell carcinoma of noncirrhotic liver - Immunohistochemical discrimination of hepatocellular and cholangiocellular origin

The incidence of hepatocellular carcinoma (HCC) is low in Europe, particularly in noncirrhotic livers (1). HCC consists of typical cytological attributes: the nuclear/cytoplasmic ratio is high, the cells are polyglonal, and the cytoplasm is finely granular and more basophilic than that of the surrounding liver cells. In this part of the world, clear cell carcinoma is an uncommon cytological variant of HCC that merits special attention. The tumor is predominantly or wholly composed of cells with clear cytoplasm, which is due to the presence of glycogen and lipids that are dissolved by routine histologic pressing (2). This variant may pose a diagnostic dilemma since it resembles other clear cell carcinomas originating in the adrenals, kidneys, ovaries, lungs, pancreas, and other organs (3-5). Unless specific features of hepatocellular carcinoma can be demonstrated, the diagnosis of primary clear cell hepatocellular carcinoma remains uncertain. We report two very rare cases of primary clear cell carcinoma in the noncirrhotic liver, in which the final differential diagnosis between hepatocellular and bile duct origin could be made by cytohistologic features from a needle aspirate, and provide diagnostic recommendations for these tumors.