HEPATIC UNDIFFERENTIATED (EMBRYONAL) SARCOMA ARISING IN A MESENCHYMALHAMARTOMA

We report the case of a hepatic undifferentiated (embryonal) sarcoma ( UES) arising within a mesenchymal hamartoma (MH) in a 15-year-old girl . Mapping of the tumor demonstrated a typical MH transforming graduall y into a UES composed of anaplastic stromal cells. When evaluated by f low cytometry, the MH was diploid and the UES showed a prominent aneup loid peak. Karyotypic analysis of the UES showed structural alteration s of chromosome 19, which have been implicated as a potential genetic marker of MH. The histogenesis of MH and UES is still debated, and rep orts of a relationship between them, although suggested on the basis o f histomorphologic similarities, have never been convincing. The histo logic, flow cytometric, and cytogenetic evidence reported herein sugge sts a link between these two hepatic tumors of the pediatric populatio n.