Although Noonan syndrome (NS) is occasionally associated with embryonal solid tumors, there has been no report of hepatoblastoma in NS. We identified hepatoblastoma spreading into bilateral hepatic lobes in a 1-month-old NS patient with a heterozygous PTPN11 mutation (Asn308Asp). This finding suggests the potential relevance of constitutively activated RAS/MAPK signaling in the development of hepatoblastoma. Pediatr Blood Cancer 2008;50:1274–1276. © 2008 Wiley-Liss, Inc.