Hepatoblastoma with cholangioblastic features ('cholangioblastic hepatoblastoma') and other liver tumors with bimodal differentiation in young patients.

In a subset of hepatoblastomas, differentiation of neoplastic cells can proceed along a pathway resulting in cholangiocyte-like cells. These cells either occur as single, immunohistochemically detectable elements, or form incomplete and complete duct-like profiles in continuation with embryonal, fetal or macrotrabecular hepatoblastoma components. As a working formulation it is proposed to employ the term, hepatoblastoma with cholangioblastic features (or 'cholangioblastic' hepatoblastoma), to denote such lesions. This bimodal differentiation presents itself in other rare tumors in the form of complex arrays of duct-like cells encircling nests of neoplastic hepatocyte lineage cells, in some way mimicking a ductal plate. A possible pathogenetic pathway is suggested, i.e., uni- or bipotential neoplastic progenitors switch into either of the two lineages. Copyright 2002 Wiley-Liss, Inc.