Mixed hepatocellular carcinoma and hepatoblastoma: cytohistopathologic findings and differential diagnosis.

BACKGROUND: Hepatocellular carcinoma (HCC) accounts for approximately 80% of all the primary malignant tumors of the liver. Hepatoblastoma (HBL) is the most common primary malignant neoplasm of the liver in childhood, and extremely rare in adults. To the best of our knowledge, this is the first report of an adult case with cytopathologic description of a combined HCC and HBL, occurring in a noncirrhotic liver. CASE: A 24-year-old male was admitted to the hospital with right-sided abdominal pain. Masses in the liver were detected radiologically. Fine-needle aspiration biopsy and core-needle biopsy revealed a malignant hepatocellular tumor with features of both HCC and HBL. CONCLUSION: In the present case among the distinct HCC cell groups, areas of smaller and more primitive cells consistent with embryonal type HBL and some other groups of cells with intermediate morphology were observed. These findings suggested the probable single stem cell origin of the tumor with differentiation to both cell groups rather than a combination of two different tumors. Therefore, the term 'malignant hepatocellular tumor' could also be considered to define this particular tumor. This case provides support to the previous reports in which HBL areas are described in HCC.