Diagnostic Ultrasound - Abdomen and Pelvis

Focal Nodular Hyperplasia
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Diagnoses: Liver
○ Color Doppler ultrasound/contrast enhanced ultrasound
– Spoke-wheel pattern vessels, brisk centrifugal
enhancement on arterial phase, especially in smaller
lesions
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Often asymptomatic (in 50-90% incidental finding)
○ Vague abdominal pain (10-15%) due to mass effect
○ Hepatomegaly and abdominal mass: Very rare
○ Lab data: Usually normal liver function tests
○ Diagnosis
– Characteristic imaging findings
– Core needle biopsy (include central scar)
DIFFERENTIAL DIAGNOSIS
Hepatic Adenoma
• Usually heterogeneous echogenicity due to hemorrhage,
necrosis, or fat
• Rarely has central scar
• Washout on portal/delayed phase of CEUS/CT/MR
Fibrolamellar Carcinoma
Demographics
• Usually Large (> 12 cm) heterogeneous mass
• Large fibrous central scar with calcification
○ Hypointense on T2WI
• Biliary, vascular, & nodal invasion may be present
• Metastases (70% of cases)
Cavernous Hemangioma
• Isoechoic or heterogeneous lesions may simulate FNH
• Nodular peripheral centripetal enhancement, no central
scar
Natural History & Prognosis
• No risk of malignant transformation
Hepatic Metastasis
• No hemorrhagic complication
• Multiple lesions, known primary tumor
Treatment
PATHOLOGY
• Discontinuation of oral contraceptives
• FNH seldom requires surgery
General Features
• Etiology
DIAGNOSTIC CHECKLIST
○ Ischemia caused by occult occlusion of intrahepatic
vessels
Consider
– Followed by hyperplastic response to abnormal
vasculature
○ Localized arteriovenous shunting caused by anomalous
Image Interpretation Pearls
arterial supply
○ Oral contraceptives do not cause FNH, but have trophic
effect on growth
• Associated abnormalities
○ Hepatic hemangioma (23%)
○ Hepatic adenoma
○ Multiple lesions of FNH are associated with
SELECTED REFERENCES
– Brain neoplasms: Meningioma, astrocytoma
– Vascular malformations of various organs
Gross Pathologic & Surgical Features
• Localized, well-delineated, usually solitary (80%),
subcapsular mass
• No true capsule, frequently central fibrous scar
• No intratumoral calcification, hemorrhage, or necrosis
Microscopic Features
• Normal hepatocytes with large amounts of fat,
triglycerides, & glycogen
• Thick-walled arteries in fibrous septa radiating from center
to periphery
• Proliferation & malformation of bile ducts lead to slowing
of bile excretion
• Absent portal triads & central veins
• Difficult differentiation from regenerative cirrhotic nodule
and liver adenoma by histology
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• Age
○ Common in young to middle-aged women
– 3rd-4th decades of life
• Gender
○ M:F = 1:8
• Epidemiology
○ 4% of all primary hepatic tumors in pediatric population
○ 3-8% in adult population
• Imaging is more reliable than histology in making diagnosis
of FNH
• Immediate, intense, homogeneously enhancing lesion on
arterial phase followed rapidly by isodensity on venous
phase with delayed enhancement of scar
• Classic FNH looks like cross section of orange (central "scar,"
radiating septa)
1. Kong WT et al: Contrast-enhanced ultrasound in combination with color
Doppler ultrasound can improve the diagnostic performance of focal
nodular hyperplasia and hepatocellular adenoma. Ultrasound Med Biol.
41(4):944-51, 2015
2. Li W et al: Differentiation of atypical hepatocellular carcinoma from focal
nodular hyperplasia: diagnostic performance of contrast-enhanced US and
microflow imaging. Radiology. 140911, 2015
3. Suh CH et al: The diagnostic value of Gd-EOB-DTPA-MRI for the diagnosis of
focal nodular hyperplasia: a systematic review and meta-analysis. Eur Radiol.
25(4):950-60, 2015
4. Bertin C et al: Contrast-enhanced ultrasound of focal nodular hyperplasia: a
matter of size. Eur Radiol. 24(10):2561-71, 2014
5. Pei XQ et al: Quantitative analysis of contrast-enhanced ultrasonography:
differentiating focal nodular hyperplasia from hepatocellular carcinoma. Br J
Radiol. 86(1023):20120536, 2013
6. Wang W et al: Contrast-enhanced ultrasound features of histologically
proven focal nodular hyperplasia: diagnostic performance compared with
contrast-enhanced CT. Eur Radiol. 23(9):2546-54, 2013
7. Kamaya A et al: Hypervascular liver lesions. Semin Ultrasound CT MR.
30(5):387-407, 2009