Diagnostic Ultrasound - Abdomen and Pelvis

Cystic Liver Lesion
Differential Diagnoses: Liver
DIFFERENTIAL DIAGNOSIS
Common
• Hepatic Cyst
• Polycystic Liver Disease
• Pyogenic Hepatic Abscess
• Recent Hepatic Hemorrhage
• Biloma
• Vessels
• Biliary Cystadenoma/Cystadenocarcinoma
• Hepatic Echinococcal Cyst
• Peribiliary Cyst
• Biliary Hamartoma
• Amebic Abscess
• Dilated Bile Ducts
Less Common
• Hepatic Lymphoma
• Hepatic Metastases
• Ciliated Hepatic Foregut Cyst
Rare but Important
• Caroli Disease
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Lesions have few to no echoes within them
• Termed "simple"
○ When unilocular with no internal septa and not lobulated
or irregular in contour
• Anechoic lesions tend to be round or oval-shaped with
smooth contour on all surfaces
• Degree of posterior acoustic enhancement or shadowing
and thickness of wall help limit differential diagnoses
Helpful Clues for Common Diagnoses
• Hepatic Cyst
○ Anechoic
○ Smooth borders but occasionally lobulated
○ Thin or imperceptible wall with no mural nodule
○ Well-defined back wall
○ Posterior acoustic enhancement
○ Often subcapsular and may bulge liver contour
○ Do not cross liver segments
○ Do not communicate with each other or bile ducts
○ No internal or mural vascularity but may distort adjacent
vessels
○ May have internal echoes or septations after
hemorrhage or infection
• Polycystic Liver Disease
○ May have concomitant autosomal dominant polycystic
kidney disease
– May make diagnosis of polycystic liver disease easier
– Less likely to have pancreatic cysts as well
○ Individual cysts look identical to simple hepatic cysts
○ Number of cysts increases with age
○ When numerous and sizable, liver architecture is
distorted,making diagnosis easier
○ Some cysts may be complicated by hemorrhage
– Become hyperechoic or contain debris or septa
• Pyogenic Hepatic Abscess
○ Anechoic (50%), hyperechoic (25%), hypoechoic (25%)
○ Small or microabscesses closely simulate small cysts
– May have internal echogenic debris when large
○ Variable in shape with thin or thick walls
○ Borders range from well defined to irregular
○ Tendency to cluster
– Group of small pyogenic abscesses coalesce into
single large cavity
○ May have adjacent hepatic parenchymal edema
– Appears hypoechoic with coarse echo pattern ±
vascularity
– Vascularity may be seen in thick-walled portion
○ Diagnosis based on combination of clinical and
sonographic features
• Recent Hepatic Hemorrhage
○ May be due to direct trauma, coagulopathy,
surgery/biopsy
○ Initially traumatic hematoma is usually echogenic
– Becomes anechoic after a few days
– May have pseudowall of compressed liver
parenchyma
○ Contour may be smooth or irregular
○ May be secondary hemorrhage into preexisting mass
– Adenoma, hepatocellular carcinoma, metastasis, etc.
– Usually not completely anechoic
• Biloma
○ Almost always secondary to trauma
– Difficult to differentiate from traumatic hematoma
□ Hematomas show debris, septations over time
□ Bilomas remain anechoic
○ Round or oval in shape
○ Fluid content may be anechoic with posterior acoustic
enhancement
– Suggests fresh biloma
○ Thin capsule wall usually not discernible
○ Larger lesions may compress adjacent liver
surface/architecture
○ Communicates with biliary tree
○ No vascularity within lesion
• Vessels
○ Portal veins: Venectasia, varicosities, collaterals from
portal hypertension
○ Hepatic veins: Venectasia, Budd-Chiari, etc.
○ Hepatic arteries: Aneurysms, shunts, vascular
malformation
○ Use of color Doppler
– Confirm vascular nature and vessel type
• Biliary Cystadenoma/Cystadenocarcinoma
○ Well-defined, multiloculated, anechoic or hypoechoic
mass
○ Highly echogenic septa
○ May see internal echoes with complex fluid,
calcifications, mural/septal nodules, or papillary
projections
– More commonly associated with biliary
cystadenocarcinoma
○ Color Doppler: Septal vascularity
○ Most commonly seen in middle-aged women
• Hepatic Echinococcal Cyst
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