Multiple Liver Lesions

Alexander J. Towbin, MD

DIFFERENTIAL DIAGNOSIS

Common

Hemangioendothelioma/Hemangioma
Hepatic Pyogenic Abscess
Metastases
- Neuroblastoma
- Wilms Tumor
- Lymphoma/Leukemia
Hepatoblastoma

Less Common

Mesenchymal Hamartoma
Nodular Regenerative Hyperplasia

Rare but Important

Caroli Disease
Peliosis Hepatis
Angiomyolipoma
Echinococcosis
Hepatocellular Carcinoma

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Various causes of multiple liver lesions
- Benign and malignant
Primary hepatic neoplasms are uncommon
0.5-2% of all pediatric neoplasms
2/3 are malignant
Overlap in imaging appearance
- Biopsy often required
Differential diagnosis can be focused by age
Lab tests may be helpful in forming differential diagnosis

Helpful Clues for Common Diagnoses

Hemangioendothelioma/Hemangioma
- a.k.a. infantile hepatic hemangioma
- Most common benign hepatic tumor
- 85% diagnosed in 1st 6 months
- Skin hemangiomas present in ˜ 50%
- Single, multiple, or diffuse lesions
- Diffuse lesions often have severe clinical course
  - Can cause massive hepatomegaly leading to compression of inferior vena cava and thoracic cavity
  - Mass effect can lead to abdominal compartment syndrome and multiorgan failure
  - Can be associated with severe hypothyroidism
Hepatic Pyogenic Abscess
- Associated with immunodeficiency, systemic infection, abdominal inflammatory processes, and chronic granulomatous disease
  - S. aureus most common organism
  - Fungal infections and B. henselae associated with microabscesses
- Can be solitary or multiple
  - Multiple in 20-25% of children and up to 70% in neonates
- Risks in neonate include necrotizing enterocolitis and umbilical vein catheterization
- US useful for diagnosis and follow-up
Metastases
- Neuroblastoma and Wilms tumor most common
  - Neuroblastoma metastasizes to liver (15%)
  - Wilms tumor metastasizes to liver (12%)
- Hepatic metastases more common overall than primary hepatic tumors
- Can appear as discrete nodules or diffuse hepatic involvement
Hepatoblastoma
- Most common pediatric hepatic malignancy
  - Majority of patients diagnosed are < 18 months of age
- More common in boys
- Associated with low birth weight, hemihypertrophy, Beckwith-Wiedemann, familial adenomatous polyposis, trisomy 18, and fetal alcohol syndrome
- 90% have increased serum α-fetoprotein
- Most common in right lobe of liver
  - Bilateral disease in 35%
- Calcifications in 40-55%
- Usually solitary solid mass
  - Can be multifocal although there is usually 1 dominant mass

Helpful Clues for Less Common Diagnoses

Mesenchymal Hamartoma
- 2nd most common benign hepatic mass
- Typically diagnosed in 1st 2 years of life
- Often presents as large RUQ mass
  - 75% in right lobe
  - α-fetoprotein may be moderately elevated
- Multiloculated cystic mass
  - Mixed cystic and solid
  - May be small or large
  - Multiple tiny cysts may appear solid
  - On US, septae of cysts may be mobile
- Rare malignant transformation to undifferentiated embryonal sarcoma
- Treatment via excision
Nodular Regenerative Hyperplasia
- Multiacinar regenerative lesion of liver in noncirrhotic liver
- Associated with systemic diseases, such as vasculitis, collagen disorders, cardiovascular disorders, and neoplasms
- Can cause portal hypertension
- Can occur after spontaneous portal vein thrombosis
- Radiologic findings not specific

Helpful Clues for Rare Diagnoses

Caroli Disease
- a.k.a. type 5 choledochal cyst
  - May be associated with autosomal recessive polycystic kidney disease
- Congenital cystic dilation of intrahepatic bile ducts
- Patients present with recurrent cholangitis or portal hypertension
Peliosis Hepatis
- Multiple blood-filled cavities
- Rare in children
  - Associated with underlying chronic conditions, such as cystic fibrosis, malnutrition, Fanconi anemia, Marfan syndrome, and adrenal tumors
Angiomyolipoma
- Associated with tuberous sclerosis
- Less common than renal angiomyolipoma
- Often multiple when present
- Lesions have imaging characteristics of fat
Echinococcosis
- a.k.a. hydatid disease
- Most common in Mediterranean, Middle East, eastern Europe, Africa, South America, China, and Australia
- Generally asymptomatic
- Appears as single or multiple cysts
  - Daughter cysts present in 75%
  - Cysts slowly expand over years
Hepatocellular Carcinoma
- 2nd most common hepatic malignancy in children
- Rare before age 5
- More common in males
- Most pediatric cases not associated with prior liver disease (> 60%)
  - Can be associated with preexisting cirrhosis due to biliary atresia, Fanconi syndrome, viral hepatitis, hereditary tyrosinemia, or glycogen storage disease
  - Other risk factors: Prior androgen steroid treatment, oral contraceptives, methotrexate
- Metastases common at diagnosis
  - Regional lymph nodes, lungs, bone
- Disease is multifocal in > 50%
  - Multifocal tumors influence overall survival and possibility of surgical resection