Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome, caused by alterations in a cluster of imprinted genes located within the chromosome region 11p15.5. Common clinical features are overgrowth, macroglossia, lateralized overgrowth, abdominal wall defects, neonatal hypoglycemia and an increased risk of embryonal tumors, such as hepatoblastomas. Periodic screening for abdominal tumors is recommended. Vascular tumors are uncommon in BWS. Diffuse infantile hepatic hemangiomas (DIHHs) are rare vascular tumors with potentially lethal complications, in particular acquired consumptive hypothyroidism, high-output cardiac failure, liver failure and abdominal compartment syndrome. We describe a 2-month-old patient with hallmark clinical features of BWS and confirmed a genetic diagnosis with mosaic paternal uniparental disomy of chromosome 11p15.5 (UPDpat). The patient developed hepatomegaly and elevated alpha-fetoprotein (AFP) and was therefore suspected of having a hepatoblastoma. Abdominal echo-color Doppler and a CT-scan allowed diagnosis of DIHHs. She was closely monitored and underwent treatment with propranolol. Oral propranolol was effective in reducing hepatic lesions without side effects. This report may suggest that vascular tumors can also be associated with BWS.© 2020 Wiley Periodicals LLC.