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Neonatal Liver Masses

A systematic imaging approach to the five key diagnostic entities

Pediatric Radiology Hepatic Imaging Neonatal Vascular Anomalies

20 min

Intermediate

5 Practice Questions

7 References

When you have finished the module and the practice questions, you can attempt the Board Practice Questions, which will be graded and recorded.

Learning Objectives

Module Overview

After completing this module you will be able to:

• Identify the five neonatal liver mass types and their defining imaging features
• Distinguish congenital from infantile hemangioma based on timing of onset
• Recognize the multiloculated cystic pattern of mesenchymal hamartoma
• Apply age-adjusted AFP in the workup of hepatoblastoma
• Describe the associations of infantile hemangioma including hypothyroidism and cutaneous lesions
• Construct a systematic differential for a neonatal liver mass from imaging phenotype

Lecture Module

Video Presentation

Neonatal Liver Masses — PedRad Academy Presentation

Mass Reference Cards

5 Entities

Benign

Congenital Hemangioma

Present and maximum size at birth

Age / Epidemiology

Present and maximum size at birth

Ultrasound

Well-defined, unifocal, hypervascular, heterogeneous

CT / MRI

Early peripheral enhancement, centripetal fill-in, arteriovenous shunting

Other Key Features

Can present with cardiac failure; regresses over time

Benign

Infantile Hemangioma

Develops postnatally · Not present at birth

Age / Epidemiology

Develops postnatally

Ultrasound

Multiple; hypoechoic with hyperechoic rim or hyperechoic; may or may not be hypervascular

CT / MRI

Early arterial enhancement, possible washout on delayed phase

Other Key Features

Associated cutaneous lesions; associated hypothyroidism

Screen TSH: Hypothyroidism via type 3 iodothyronine deiodinase. GLUT-1 positive. Propranolol first-line.

Benign

Mesenchymal Hamartoma

<2 years · May be prenatal

Age / Epidemiology

<2 years; may be prenatal

Ultrasound

Multiloculated cystic mass, septations

CT / MRI

Predominantly cystic with septa, minimal enhancement, may have solid areas

Other Key Features

Large, cystic, septated, minimal enhancement

AFP normal — key distinguishing point from hepatoblastoma. Surgical resection curative.

Malignant

Hepatoblastoma

<5 years · Rare in neonates

Age / Epidemiology

<5 years; rare in neonates

Ultrasound

Solid, heterogeneous, ± calcifications

CT / MRI

Well-defined, solid, lobulated, arterial enhancement, calcifications, necrosis

Other Key Features

Elevated AFP (age-adjusted); calcifications; solid; lobulated

Age-adjusted AFP is critical. Neonatal AFP is physiologically very high; adult reference ranges must not be applied before 8–12 months of age.

Malignant

Metastatic Neuroblastoma

Neonates with known primary · Adrenal/retroperitoneal · Multiple hepatic lesions

Age / Epidemiology

Neonates with known primary

Ultrasound

Multiple hypoechoic lesions

CT / MRI

Multiple lesions, variable enhancement, ± calcifications

Other Key Features

Adrenal/retroperitoneal primary; multiple hepatic lesions

Stage MS: MYCN non-amplified tumors typically undergo spontaneous regression. Massive hepatic disease causing respiratory compromise may require treatment regardless of biology.

At-a-Glance Comparison

Quick Reference Table

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

Practice Questions

5 Questions · Single Best Answer

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1

A term neonate presents with a hepatic mass detected on prenatal ultrasound at 28 weeks. Postnatal imaging demonstrates a well-defined, unifocal, hypervascular, heterogeneous lesion. Doppler shows arteriovenous shunting. Echocardiography reveals elevated cardiac output. Which single feature most reliably distinguishes this lesion from infantile hemangioma?

AArteriovenous shunting on Doppler BUnifocal rather than multifocal distribution CThe mass was present and at maximum size at birth DHeterogeneous echotexture EHigh-output cardiac failure

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Correct Answer: C

The defining feature of congenital hemangioma is that it is present and at its maximum size at birth — confirmed here by prenatal detection at 28 weeks. Infantile hemangioma develops postnatally and is not present at birth. AV shunting, cardiac failure, unifocal distribution, and heterogeneous echotexture may all occur in congenital hemangioma but are not exclusive to it. The temporal relationship to birth is the single most reliable distinguishing criterion between the two entities.

2

An 8-week-old girl develops multiple erythematous skin lesions over the first month of life. She was well at birth with normal prenatal imaging. Abdominal ultrasound reveals multiple hepatic lesions that are hypoechoic with hyperechoic rims. Which laboratory abnormality is most specifically associated with this diagnosis?

AElevated serum AFP BThrombocytopenia and consumptive coagulopathy CElevated TSH (associated hypothyroidism) DElevated urinary catecholamines EHypoglycemia

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Correct Answer: C

The clinical picture is classic for infantile hemangioma: postnatal development, multiple hepatic lesions (hypoechoic with hyperechoic rim), and cutaneous lesions. The specific laboratory association is hypothyroidism (elevated TSH). Infantile hemangioma cells express type 3 iodothyronine deiodinase, which inactivates circulating T3 and T4. TSH screening is mandatory in all infants with hepatic hemangiomas. Thrombocytopenia and coagulopathy (B) characterize Kasabach-Merritt phenomenon in kaposiform hemangioendothelioma — a different entity. Catecholamines (D) suggest neuroblastoma.

3

A 14-month-old boy presents with increasing abdominal girth. MRI demonstrates a large hepatic mass that is predominantly cystic with thin internal septations and minimal enhancement. There is no significant solid component. Serum AFP is normal for age. What is the most likely diagnosis?

AHepatoblastoma BMesenchymal hamartoma CCongenital hemangioma DMetastatic neuroblastoma EInfantile hemangioma

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Correct Answer: B

Mesenchymal hamartoma presents in children under 2 years with a large, cystic, septated hepatic mass and minimal enhancement. Normal AFP is the critical distinguishing feature from hepatoblastoma when solid-appearing areas are present. Hepatoblastoma (A) is solid with calcifications and elevated AFP. The hemangioma entities are vascular and would not present as predominantly cystic septated masses. The pattern — large, cystic, septated, minimal enhancement, normal AFP — is the diagnostic signature of mesenchymal hamartoma.

4

A 2.5-year-old boy presents with a large right hepatic lobe mass. CT shows a well-defined, solid, lobulated lesion with internal calcifications, arterial enhancement, and central necrosis. Serum AFP is 26,000 ng/mL. Which statement regarding AFP interpretation is most accurate?

AAn AFP of 26,000 ng/mL is physiologically normal for a 2.5-year-old and does not support malignancy BAFP must be interpreted using age-adjusted reference ranges; at 2.5 years, this level is markedly elevated and strongly supports hepatoblastoma CAFP elevation at this age exclusively indicates a gonadal germ cell tumor DAFP is not a clinically useful biomarker for pediatric hepatic tumors EA mildly elevated AFP in this age group does not warrant additional imaging

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Correct Answer: B

AFP must always be interpreted using age-adjusted reference ranges. AFP is physiologically very high at birth and declines to adult reference levels only by approximately 8–12 months. By age 2.5, adult ranges apply, and an AFP of 26,000 ng/mL is markedly elevated. Combined with a solid, lobulated, calcified hepatic mass with necrosis, this is highly consistent with hepatoblastoma. AFP is used for diagnosis and as a marker of treatment response. Applying adult cutoffs to infants is a recognized clinical pitfall that can produce false reassurance.

5

A 3-week-old neonate presents with massive hepatomegaly and respiratory distress. Abdominal ultrasound shows multiple hypoechoic lesions throughout the liver. CT demonstrates a right suprarenal mass with calcifications and multiple hepatic lesions with variable enhancement. Urinary catecholamines are elevated. Which of the following best characterizes this entity?

AUniformly poor prognosis due to extent of hepatic involvement BMetastatic neuroblastoma with an adrenal/retroperitoneal primary and multiple hepatic lesions; MYCN non-amplified stage MS tumors typically undergo spontaneous regression CFavorable prognosis only if complete surgical resection of hepatic metastases can be achieved DThis presentation is inconsistent with neuroblastoma, which does not spread to the liver in neonates EPrognosis depends solely on the size of the adrenal primary

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Correct Answer: B

This is metastatic neuroblastoma with an adrenal primary and multiple hepatic lesions. In neonates this corresponds to stage MS, defined by: age <18 months, localized primary, and metastases confined to liver, skin, or bone marrow. MYCN non-amplified stage MS tumors typically undergo spontaneous regression. However, massive hepatic disease causing respiratory compromise — as in this case — may require low-dose chemotherapy regardless of biology, to relieve the mechanical burden from the hepatic involvement.

References

7 Key Papers

1. Chavhan GB, Schooler GR, Tang ER, et al. Optimizing Imaging of Pediatric Liver Lesions: Guidelines From the Pediatric LI-RADS Working Group. RadioGraphics. 2023;43(1):e220043. PubMed
2. Chung EM, Cube R, Lewis RB, Conran RM. From the Archives of the AFIP: Pediatric Liver Masses Part 1. Benign Tumors. RadioGraphics. 2010;30(3):801–826. PubMed
3. Li L, Liu W, Wen R, Jin K. Computed Tomography Imaging and Clinical Features of Congenital Hepatoblastoma. Medicine. 2020;99(31):e21174. PubMed
4. Saeed O, Saxena R. Primary Mesenchymal Liver Tumors of Childhood. Seminars in Diagnostic Pathology. 2017;34(2):201–207. PubMed
5. Chung EM, Lattin GE, Cube R, et al. From the Archives of the AFIP: Pediatric Liver Masses Part 2. Malignant Tumors. RadioGraphics. 2011;31(2):483–507. PubMed
6. Rajasimman AS, Patil V, Gala KB, et al. Accuracy of Contrast-Enhanced CT in Liver Neoplasms in Children Under 2 Years Age. Pediatric Radiology. 2024;54(12):1946–1955. PubMed
7. Karmazyn B, Rao GS, Johnstone LS, et al. Diagnosis and Follow-Up of Incidental Liver Lesions in Children. Journal of Pediatric Gastroenterology and Nutrition. 2022;74(3):320–327. PubMed

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