Case: AP144
Contributor's Comment: This case is intended to show a dysplastic nodule (DN) transforming into hepatocellular carcinoma (HCC). The carcinoma is sufficiently diagnostic on H&E with the degree of architectural and nuclear abnormality and nodule-in-nodule pattern.

Most participants cannot point out the presence of a pre-existing DN; only 2 marks are deducted in this case as HCC has already arisen and the eventual outcome of the patient is not much affected irrespective of whether the pre-existing DN is recognised. Those who have not mentioned the presence of cirrhosis have a further 8 marks deducted because of an incomplete diagnosis which has an important impact on the prognosis. Participants 515 and 517 cannot definitely diagnose HCC based on H&E stain and have more marks deducted. Focal nodular hyperplasia is a totally invalid differential diagnosis, and hence no score.

In this case, you can easily compare side by side the cytological and architectural features of a DN with non-neoplastic hepatocytes and HCC. Just like dysplasia in other epithelia, the N/C ratio is highest in the high-grade dysplastic hepatocytes with much less cytoplasm than normal or carcinomatous hepatocytes. They are also more uniformly looking. The cell plates are 2-3 cell thick and not discontinuous, without significant loss of reticulin or extensive CD34 staining as in HCC (see photos). A definitive high-grade DN should be treated like HCC by less aggressive means.