We report a case of hepatoblastoma in a 10-year-old girl with mosaic-type trisomy 18. A comprehensive literature review reveals only 2 cases involving mosaic trisomy 18 patients. Our patient underwent an abbreviated chemotherapy course before complete surgical resection. Her hepatoblastoma did not contain cells with trisomy 18. The conservative management approach resulted in a successful outcome; she remains disease free >2 years after surgery. Along with presenting a literature review, this report demonstrates a favorable outcome in a mosaic trisomy 18 child with hepatoblastoma where tumor cells lacked a trisomy 18 karyotype.