Diagnostic Ultrasound - Abdomen and Pelvis

Hepatic Lymphoma
TERMINOLOGY
Definitions
• Neoplasm of lymphoid tissues in liver
IMAGING
General Features
• Best diagnostic clue
○ No known specific imaging findings for diagnosis of
hepatic lymphoma
○ Lobulated, hypoechoic/low-density, hypovascular masses
• Location
○ Favors periportal areas
– Due to high content of lymphatic tissue
○ Liver is often secondary site for lymphoma
• Size
○ Variable; from few millimeters to centimeters
• Morphology
○ Discrete lesions
– Solitary or multiple masses in liver
– More likely to be primary non-Hodgkin lymphoma
(NHL) or AIDS-associated lymphoma
○ Diffuse infiltration
– Usually secondary site in Hodgkin disease (HD) or NHL
– Often difficult to detect on imaging
• Key concepts
○ Hepatic lymphoma is detected in vivo in < 10% of cases
○ Primary hepatic lymphoma is rare
– Mostly seen in immunocompromised patients
○ Secondary hepatic involvement is more common than
primary
– Seen in > 50% of patients with lymphoma on autopsy
○ Generally more common in immunosuppressed patients
– Transplant recipients and AIDS patients are at high risk
○ Types of lymphoma: NHL > HD
Ultrasonographic Findings
• Grayscale ultrasound
○ Discrete form
– Multiple, well-defined nodules or masses
– Hypoechoic or anechoic lesions
□ Hypoechogenicity probably due to high cellular
density and lack of background stroma
– Large or conglomerate masses may appear to contain
septa and mimic abscesses
○ Diffuse/Infiltrative Form
– Innumerable subcentimeter hypoechoic foci, miliary in
pattern and periportal in location
– Infiltrative pattern may be indistinguishable from
normal liver
– Most are missed and only diagnosed on autopsy
○ Other signs of lymphoma
– Hepatomegaly
– Associated splenomegaly or splenic lesions
– Lymphadenopathy (periportal, paraaortic, mesenteric)
– Bowel wall thickening (infiltration)
– Ascites
CT Findings
• NECT
○ May be normal
○ Primary lymphoma
– Isodense or hypodense to liver
○ Secondary lymphoma
– Multiple well-defined, large, homogeneous, lobulated,
low-density masses
– Diffuse infiltration: Indistinguishable from normal liver
or steatosis
• CECT
○ Solid lesions with poor contrast enhancement
○ Usually homogeneous density and rarely necrotic
○ May have thin rim enhancement
○ Diffuse, infiltrative, low-density areas
MR Findings
• T1WI
○ Discrete lesion: Hypointense masses
○ Diffuse infiltration: Indistinguishable from normal liver
• T2WI
○ Discrete lesion: Hyperintense masses
○ Diffuse infiltration: Indistinguishable from normal liver
• T1WI C+
○ Poor gadolinium enhancement
○ May have rim enhancement
Nuclear Medicine Findings
• PET
○ F-18 FDG-avid lesions
– Focal or diffuse hypermetabolic activity
– Useful for staging disease
– Background metabolic activity of liver may obscure
some lesions
Imaging Recommendations
• Best imaging tool
○ Ultrasound for surveillance and monitoring lesion
progress/treatment response
• Protocol advice
○ Ultrasound detection of lesion to be followed by CECT
for disease staging
DIFFERENTIAL DIAGNOSIS
Metastases
• Peripheral rim enhancement, internal necrosis
• Often difficult to differentiate without history of primary
lesion
Multifocal/Diffuse Hepatocellular Carcinoma (HCC)
• Background cirrhotic liver
• Hypovascular HCCs mimic discrete form of hepatic
lymphoma
• Diffuse HCCs mimic infiltrative form of hepatic lymphoma
• Portal vein invasion/thrombosis
Liver Abscesses
• May see fluid content or internal debris or septations on US
• "Cluster" sign on CECT for pyogenic abscesses
• Often with atelectasis and right pleural effusion
• Typical systemic signs of infection
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Diagnoses: Liver
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