Mass Type	Age/Epidemiology	Ultrasound Features	CT/MRI Features	Other Key Features
Congenital Hemangioma	Present and maximum size at birth	Well-defined, unifocal, hypervascular, heterogeneous	Early peripheral enhancement, centripetal fill-in, arteriovenous shunting	Can present with cardiac failure, regresses over time
Infantile Hemangioma	Develops postnatally	Multiple, may or may not be hypervascular, hypoechoic with hyperechoic rim or hyperechoic	Early arterial enhancement, possible washout on delayed phase; not present at birth	Associated cutaneous lesions, develops after birth, associated hypothyroidism
Mesenchymal Hamartoma	<2 years, may be prenatal	Multiloculated cystic mass, septations	Predominantly cystic with septa, minimal enhancement, may have solid areas	Large, cystic, septated, minimal enhancement
Hepatoblastoma	<5 years, rare in neonates	Solid, heterogeneous, ± calcifications	Well-defined, solid, lobulated, arterial enhancement, calcifications, necrosis	Elevated AFP (age-adjusted), calcifications, solid, lobulated
Metastatic Neuroblastoma	Neonates with known primary	Multiple hypoechoic lesions	Multiple lesions, variable enhancement, ± calcifications	Adrenal/retroperitoneal primary, multiple hepatic lesions

References.
1. Optimizing Imaging of Pediatric Liver Lesions: Guidelines From the Pediatric LI-RADS Working Group.Chavhan GB, Schooler GR, Tang ER, et al. Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2023;43(1):e220043. doi:10.1148/rg.220043.
2. From the Archives of the AFIP: Pediatric Liver Masses: Radiologic-Pathologic Correlation Part 1. Benign Tumors.Chung EM, Cube R, Lewis RB, Conran RM. Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2010;30(3):801-26. doi:10.1148/rg.303095173.
3. Computed Tomography Imaging and Clinical Features of Congenital Hepatoblastoma: A Retrospective Analysis.Li L, Liu W, Wen R, Jin K. Medicine. 2020;99(31):e21174. doi:10.1097/MD.0000000000021174.
4. Primary Mesenchymal Liver Tumors of Childhood.Saeed O, Saxena R. Seminars in Diagnostic Pathology. 2017;34(2):201-207. doi:10.1053/j.semdp.2016.12.016.
5.From the Archives of the AFIP: Pediatric Liver Masses: Radiologic-Pathologic Correlation. Part 2. Malignant Tumors.Chung EM, Lattin GE, Cube R, et al.Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2011 Mar-Apr;31(2):483-507. doi:10.1148/rg.312105201.
6.Accuracy of Contrast-Enhanced CT in Liver Neoplasms in Children Under 2 years Age.Rajasimman AS, Patil V, Gala KB, et al.
Pediatric Radiology. 2024;54(12):1946-1955. doi:10.1007/s00247-024-05958-w.
7. Diagnosis and Follow-Up of Incidental Liver Lesions in Children.Karmazyn B, Rao GS, Johnstone LS, et al. Journal of Pediatric Gastroenterology and Nutrition. 2022;74(3):320-327. doi:10.1097/MPG.0000000000003377.