Imaging insights into pediatric liver masses: A comprehensive minireview for hepatology practice

Table 1 Definitions of pretreatment extent of disease stages used for staging of pediatric liver tumors

Stage	Definition
PRETEXT I	Three contiguous hepatic sections free of tumor. Tumor can only be present in left lateral or right posterior sections
PRETEXT II	Involvement of either one or two sections, with no tumor seen in two contiguous sections. Involvement limited to the caudate lobe is also PRETEXT II disease
PRETEXT III	Involves portions of both right and left lobes of the liver with involvement of two or three sections. Only one contiguous section remains tumor free
PRETEXT IV	Mostly multifocal disease with involvement of all four sections

PRETEXT: Pretreatment extent of disease.

Table 2 Summary of pediatric hepatic lesions from birth to six years of life

Lesion	Age	AFP	Calcifications	Imaging appearance	Quantitative metrics
Hepatoblastoma	< 5 years (peak: 6 months-3 years)	Markedly elevated (> 100000 ng/mL in many cases)	Chunky calcifications commonly seen in 50% of cases	US: Heterogeneous, solid mass, may have necrosis and calcifications. CT: Enhancing soft tissue with coarse calcifications. MRI: Isoechoic/hypoechoic on T1, hyperintense on T2, with heterogeneous enhancement	Size: > 5 cm at diagnosis. AFP: > 10000-100000+ ng/mL
Hepatic hemangioma	Neonates and infants (< 6 months)	Normal or mildly elevated (< 100 ng/mL). Limited diagnostic value	Rare. May be present in the congenital forms of hemangioma but absent in the infantile type	US: Hypoechoic or mixed echotexture, high vascularity with Doppler. CT/MRI: Vascular lesion with peripheral enhancement and centripetal fill-in	Size: Ranges from small (< 3 cm) to giant (> 5 cm). May cause high-output cardiac failure in giant hemangiomas
Mesenchymal hamartoma	< 2 years (typically < 18 months)	Normal	Rare	US and CT: Multiseptated cystic lesion interspersed with solid component. Minimal enhancement	Size: Often large (> 10 cm), displacing adjacent organs

AFP: Alpha-fetoprotein; CT: Computed tomography; MRI: Magnetic resonance imaging; US: Ultrasound.

Table 3 Summary of pediatric hepatic masses in children six years of age and older

	Age	Gender	Alpha-fetoprotein	Imaging appearance	Quantitative metrics
Hepatocellular carcinoma	> 6 years of age (bimodal peak: 10-14 years)	No gender predilection	Elevated in 50%-70% (variable; can be > 10000 ng/mL)	US: Heterogeneous mass, may show necrosis. CT/MRI: Arterial phase enhancing lesion with washout on portal/delayed phases	Size: > 5 cm at presentation. Occasional calcifications (approximately 20%). Risk factors: Chronic liver disease, metabolic disorders (e.g., tyrosinemia)
Focal nodular hyperplasia	> 6 years (mean age of 12 years)	More common in females	Normal	US: Isoechoic to hypoechoic; spoke wheel pattern of vascularity. CT and MRI: Enhancing lesion with central scar. T2 hyperintense scar, arterial enhancement with delayed central scar fill-in	Size: < 5 cm. Central scar: Present in approximately 80%. Calcification is rare
Hepatic adenoma	> 6 years (mean age of 12 years)	More common in females	Normal	US: Solid, hyperechoic or isoechoic. CT: Arterial enhancement, isoechoic/hypodense in venous phase. MRI: Variable T1/T2, early enhancement, no central scar. May show fat or hemorrhage	Size: Variable; > 5 cm increases risk of hemorrhage. Risk of rupture/malignant transformation in β-catenin-mutated subtype. Risk factors: Oral contraceptive pills or steroid use

CT: Computed tomography; MRI: Magnetic resonance imaging; US: Ultrasound.

Table 4 Todani classification of choledochal cysts

	Todani classification	Subtypes
Type I	Fusiform dilatation of the extrahepatic biliary ducts	Ia: Dilatation of entire extrahepatic bile duct. Ib: Focal segmental dilatation of extraheptic bile duct. Ic: Dilatation of the common bile duct
Type II	Saccular outpouching from the intra and extrahepatic bile duct, also known as bile duct diverticulum
Type III	Protrusion of a focally dilated intramural segment of the common bile duct into the duodenum, also known as choledochocele
Type IV	Communicating intra and extrahepatic duct cysts	IVa: Dilatation of the entire extrahepatic bile duct along with dilatation of the intrahepatic bile ducts. IVb: Cystic dilatation involving only the extrahepatic bile duct
Type V	Cystic dilatation of intrahepatic bile ducts, also known as Caroli disease
Type VI	Dilatation of only the cystic duct, a rare entity

Table 5 Summary of hepatic lesions encountered in all ages of the pediatric population

Lesion	Clinical features	Relevant laboratory investigations	Imaging appearances
Simple hepatic cyst	Asymptomatic; incidental finding; large cysts may cause abdominal pain or mass effect	Normal LFTs; no infection markers	US: Anechoic lesion with posterior acoustic enhancement. CT/MRI: Nonenhancing, fluid-filled lesion with thin wall
Choledochal cyst	Jaundice, abdominal pain, palpable mass, vomiting	LFTs abnormal in cholestasis	Magnetic resonance cholangiopancreatography/CT: Fusiform or saccular bile duct dilation showing communication with the biliary tree
Hydatid cyst	Asymptomatic in early stages; abdominal pain; rupture may cause anaphylaxis	Eosinophilia; positive Echinococcus serology	CT/MRI: Multiloculated cyst with calcifications, detached membrane (water lily sign)
Hepatic abscess	Fever, pain, jaundice, hepatomegaly; may mimic malignancy	Elevated white blood cell, CRP, ESR; positive blood cultures; abnormal LFTs	US: Hypoechoic/complex lesion, internal septations. CT: Peripheral enhancement, cluster sign, double target sign
Tuberculous liver lesions	Fever, weight loss, hepatosplenomegaly; often part of disseminated TB	Positive TB test, elevated CRP/ESR, possible acid fast bacilli in biopsy	CT/MRI: Calcified granulomas, miliary nodules, caseating necrosis, abscess formation
Lymphoma (hepatic involvement)	Fever, weight loss, hepatomegaly	Elevated lactate dehydrogenase; abnormal peripheral blood counts; possible lymphoma markers	US: Hypoechoic, ill-defined masses. CT/MRI: Multiple low-attenuation lesions, mild enhancement
Hepatic metastasis	Hepatomegaly, pain, systemic symptoms related to primary malignancy	Tumor markers (alpha-fetoprotein, catecholamines, etc.), abnormal LFTs	CT/MRI: Multiple lesions, variable enhancement, necrotic centers, target appearance

CRP: C-reactive protein; CT: Computed tomography; ESR: Erythrocyte sedimentation rate; LFTs: Liver function tests; MRI: Magnetic resonance imaging; TB: Tuberculosis; US: Ultrasound.