Diagnostic Ultrasound - Abdomen and Pelvis

Target Lesions in Liver
Differential Diagnoses: Liver
DIFFERENTIAL DIAGNOSIS
Common
• Hepatic Metastases
• Hepatocellular Carcinoma (HCC)
• Hepatic Lymphoma
• Hepatic Adenoma
• Fungal Hepatic Abscess
• Amebic Hepatic Abscess
• Pyogenic Hepatic Abscess
Less Common
• Hepatic Atypical Hemangioma
• Hepatic Hematoma
Rare but Important
• Sarcoidosis
• Kaposi Sarcoma
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Target sign: Echogenic center surrounded by hypoechoic
rim
○ a.k.a. "bull's-eye" lesions
○ Malignancy far outnumbers other causes
• "Reverse target": Hypoechoic core with hyperechoic rim
Helpful Clues for Common Diagnoses
• Hepatic Metastases
○ Solid central tumor with hypoechoic halo
– Halo most likely related to compressed hepatic tissue
along with zone of cancer cell proliferation
○ Alternating layers of hyper- and hypoechoic tissue
○ Usually from aggressive primary tumors
– Classic example: Bronchogenic carcinoma
• Hepatocellular Carcinoma (HCC)
○ Background of cirrhosis, portal hypertension, ascites
○ Rare for cirrhotic livers to develop metastases from
nonhepatic primary
– Any mass in cirrhotic liver is more likely HCC than
metastasis
• Hepatic Lymphoma
○ Vast majority are uniformly hypoechoic
○ Splenomegaly or splenic lesions, lymphadenopathy,
thickened bowel wall provide clues toward diagnosis
• Hepatic Adenoma
○ Usually isoechoic or slightly hypoechoic
○ Complications such as hemorrhage, central necrosis
make center echogenic
○ Occasional hypoechoic rim forms target-like appearance
• Fungal Hepatic Abscess
○ Often multiple lesions
○ Typically in immunocompromised patient
• Amebic Hepatic Abscess
○ Iso- to mildly hyperechoic center with hypoechoic halo
○ Abuts liver capsule
• Pyogenic Hepatic Abscess
○ Central hyperechoic inflammatory nodule surrounded by
hypoechoic halo of fibrosis
○ Cluster sign: Cluster of small pyogenic abscesses that
coalesce into single large cavity
○ Lobulated or irregular contour
Helpful Clues for Less Common Diagnoses
• Hepatic Atypical Hemangioma
○ Hypoechoic center with thick or thin hyperechoic rim
– "Typical atypical" appearance (up to 40%)
– Hypoechogenicity seem to be related to predominant
fibrous stroma
• Hepatic Hematoma
○ May have laceration tract leading to hepatic surface
○ Multiple organs involved if traumatic cause
SELECTED REFERENCES
1. Virmani J et al: Characterization of primary and secondary malignant liver
lesions from B-mode ultrasound. J Digit Imaging. 26(6):1058-70, 2013
2. Kraus GJ et al: The reverse target sign in liver disease: a potential ultrasound
feature in cirrhotic liver nodules characterization. Br J Radiol. 78(928):355-7,
2005
(Left) Transverse abdominal
US in a patient with breast
cancer metastases to the liver
shows that the metastases
have a classic target
appearance ſt in which
rounded echogenic lesions are
surrounded by a hypoechoic
rim. (Right) Transverse
abdominal US in a patient with
sarcoma metastases to the
liver shows multiple small
hepatic metastases have a
target appearance ſt in which
echogenic rounded lesions are
surrounded by a hypoechoic
rim. Background liver shows
diffuse steatosis .
Hepatic Metastases
Hepatic Metastases
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