Undifferenziertes kleinzelliges Hepatoblastom

Undifferentiated small-cell hepatoblastoma (HB) is a rare malignant tumor of childhood. The cell of origin is supposed to be a pluripotential, probably entodermal, stem-cell. Differential diagnosis of this type of HB is difficult among the group of small round and blue cell malignant tumors of children. The immunohistochemically determined coexpression of cytokeratin 8, 18, and 19 and of vimentin and actin, regularly in the absence of alpha-fetoprotein expression may be diagnostically helpful. We present the case of an undifferentiated small-cell HB of a 15-month-old girl with agenesis of the right kidney. As morphological peculiarity the tumor presented disseminated histiocytic giant cells.