Hepatic Metastases and Lymphoma

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 22/04/2025

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 3810 times

 Diffuse infiltration and low density on NECT

image Multiple well-defined, homogeneous, low-density (CECT) or high-intensity (T2WI) masses
• Liver metastases

image Hypovascular metastases: Low-density center with peripheral rim or target-like enhancement
image Hypervascular metastases: Hyperdense (intense) on arterial phase CECT or CEMR
• Cystic metastases (< 20 HU)

image Fluid levels, debris, mural nodules
• Liver-specific MR contrast agents (e.g., gadoxetate)

image Metastases: Hypointense lesions made more apparent compared with bright enhancement of liver on delayed phase imaging
• CECT is usually best as “whole body” screening test

image Even better if combined as PET/CT
image Metastases and lymphoma are usually FDG-avid masses within liver
• Decision for thermal ablation or surgical resection

image May require most sensitive tests (gadoxetate-enhanced MR, PET/CT, or intraoperative US)

TOP DIFFERENTIAL DIAGNOSES

• Multifocal fatty infiltration (steatosis)
• Multiple benign masses
• Multifocal hepatocellular carcinoma or cholangiocarcinoma

DIAGNOSTIC CHECKLIST

• In absence of a known primary tumor or other metastases:

image Hepatic lesions that are “too small to characterize” rarely represent metastases
image Lesions that are lower than blood density on NECT rarely represent metastases
image
(Left) Axial CECT shows multiple spherical liver lesions image with a “target” appearance. This is the most typical appearance for liver metastases, especially from colon cancer. Also note the focally dilated bile ducts image due to compression by the metastases.

image
(Right) Color Doppler ultrasound in the same patient shows multiple spherical liver lesions with a “target” appearance image, some containing visible blood vessels image. This is the typical appearance of metastatic colorectal carcinoma.
image
(Left) Axial T1WI C+ MR in a patient with metastatic colon cancer shows multiple liver metastases with several typical features, including a continuous ring of enhancement image.

image
(Right) Axial T2WI FS MR in the same patient shows heterogeneous hyperintensity within the hepatic metastases image. Most metastases are heterogeneously hyperintense on T2WI and hypovascular and hypointense on T1WI.

TERMINOLOGY

Abbreviations

• 

Synonyms

Definitions

• Lymphoma: Neoplasm of lymphoid tissues
• Metastases: Malignant spread of neoplasm to hepatic parenchyma

IMAGING

General Features

• Best diagnostic clue

image Lymphoma: Lobulated, low-density, hypovascular masses
image Metastases: Multiple heterogeneous, spherical lesions scattered throughout liver
• Location

image Lymphoma (HD and NHL) favors periportal areas due to high content of lymphatic tissue
• Size

image Variable; few millimeters to > 10 centimeters
• Morphology

image Usually spherical
• Key concepts

image Hepatic lymphoma

– Primary (rare)
– Secondary (more common): Seen in > 50% of patients with Hodgkin disease (HD) or non-Hodgkin lymphoma (NHL)
– High-risk groups: Transplant recipients and AIDS patients
– Types of hepatic lymphoma: NHL > Hodgkin
image Liver metastases

– Most common malignant tumor of liver

image Compared to primary malignant tumors (18:1)
– Liver is 2nd only to regional lymph nodes as site of metastatic disease
– Autopsy studies reveal 55% of oncology patients have liver metastases

CT Findings

• NECT

image Lymphoma

– Diffuse infiltration: Indistinguishable from normal liver or steatosis
image Metastases

– Isodense, hypodense, or hyperdense (melanin or calcification)
• CECT

image Lymphoma

– Diffuse infiltration and low density
– Multiple well-defined, homogeneous, low-density masses
image Hypovascular metastases

– Low-attenuation center with peripheral rim enhancement (e.g., epithelial metastases)
– Indicates vascularized viable tumor in periphery and hypovascular or necrotic center
– Rim enhancement may also be due to compressed normal parenchyma
image Hypervascular metastases

– Hyperdense in late arterial phase images
– May have internal necrosis without uniform hyperdense enhancement
– Hypo-/isodense on NECT and portal venous phase

image Often washout to become hypodense on delayed phase CECT
– Examples: endocrine (islet cell), carcinoid, thyroid and renal carcinomas, and pheochromocytoma
image Cystic metastases (< 20 HU)

– Fluid levels, debris, mural nodules

MR Findings

• T1WI

image Lymphoma and metastases: Hypointense lesions

– Melanoma metastases: Hyperintense due to melanin
• T2WI

image Lymphoma: Focal or diffusely hyperintense
image Metastases

– Moderate to high signal
– Light bulb sign: Very high signal intensity (e.g., cystic and neuroendocrine metastases)

image Mimic cysts or hemangiomas but usually with thick wall or fluid level
• T1WI C+

image Hypovascular metastases

– Same pattern of enhancement as CECT
– Low signal in center and peripheral rim enhancement
– Perilesional enhancement may be tumor vascularity or hepatic edema
image Hypervascular metastases

– Hyperintense enhancement on arterial phase
• Hepatobiliary contrast agents (e.g., gadoxetate [Eovist, Primovist])

image On delayed scans, normal liver is brightly enhanced
image Metastases are conspicuous as hypointense focal lesions
image Most sensitive, but not specific, imaging test for determining presence and number of metastases

Ultrasonographic Findings

• Grayscale ultrasound

image Hepatic lymphoma

– Multiple well-defined, hypoechoic lesions
– Diffuse form: May detect innumerable subcentimeter hypoechoic foci

image Otherwise indistinguishable from normal or fatty liver
image Hypoechoic metastases

– Usually from hypovascular tumors
image Hyperechoic metastases

– GI tract malignancy
– Vascular metastases
image Bull’s-eye or “target” metastatic lesions

– Alternating layers of hyper- and hypoechoic tissue
– Solid mass with hypoechoic rim or halo
– Usually from aggressive primary tumors
image Cystic metastases

– Almost all show complex walls and contents
image Calcified metastases

– Markedly echogenic with acoustic shadowing

Nuclear Medicine Findings

• PET

image Lymphoma and metastases

– FDG-18-avid focal lesions
– Excellent staging tool for lymphoma and metastases

image High metabolic activity of liver may obscure some lesions

Imaging Recommendations

• Best imaging tool

image Meta-analysis of sensitivity for detection of colorectal metastases

– Per patient basis

image Helical CECT: 65-72% (better if 45 g of IV iodine used)
image MR: 75-76% (much better if gadoxetate is used)
image PET: 90-95%
– Per lesion basis (all modalities have lower but similar sensitivity)

image All do better for lesions > 1.5 cm
image Gadoxetate-enhanced MR much better than CT for lesions < 1.5 cm
– More recent studies of accuracy

image Helical CT (80%), MR (92%)
image CECT is usually best as “whole body” screening test

– Even better if combined as PET CT
image Decision for thermal ablation or surgical resection

– May require most sensitive tests (gadoxetate-enhanced MR, PET/CT, or intraoperative US)
• Protocol advice

image When to obtain biphasic (arterial and venous phase) CT

– Known or suspected hypervascular primary tumor

image All “endocrine” tumors (e.g., thyroid, carcinoid, neuroendocrine pancreas, pheochromocytoma), renal cell carcinoma
image Some sarcomas, breast cancer, and melanoma metastases are best seen on arterial/biphasic CT scans

DIFFERENTIAL DIAGNOSIS

Multiple Hepatic Cysts

• No peripheral rim or central enhancement
• May have increased density or intensity due to prior bleed or infection (e.g., polycystic liver)
• No mural nodules, debris, or enhancement

Multifocal Fatty Infiltration (Steatosis)

• Focal signal dropout on opposed-phase T1 GRE MR
• Vessels course through “lesions” without disruption
• Periligamentous, perivascular distribution

Multiple Hemangiomas

• Typical peripheral, nodular, discontinuous enhancement on CECT or CEMR
• Isodense with blood vessels on NECT and CECT
• Markedly hyperintense on T2WI

Multifocal Hepatocellular Carcinoma (HCC) or Cholangiocarcinoma (CC)

• HCC: Cirrhotic liver, vascular invasion
• CC: Capsular retraction, delayed enhancement

Multiple Liver Abscesses

• Cluster sign on CT for pyogenic abscesses
• Often with atelectasis and right pleural effusion

PATHOLOGY

General Features

• Etiology

image Hypovascular liver metastases, etiology

– Lung, GI tract, pancreas, and most breast cancers
– Lymphoma, bladder, and uterine malignancy
image Hypervascular liver metastases, etiology

– Endocrine tumors, renal and thyroid cancers
– Some breast cancers, sarcomas, and melanomas
• Associated abnormalities

image Metastases: Check for extrahepatic primary tumor
image Lymphoma: High-risk groups include patients with AIDS or transplant recipients

Staging, Grading, & Classification

• Liver metastases indicate stage IV tumor

Gross Pathologic & Surgical Features

• Lymphoma: Miliary, nodular, or diffuse form
• Metastases vary in size, consistency, and vascularity

image Nodular, infiltrative, expansile, or miliary

Microscopic Features

• Hodgkin disease

image Typical Reed-Sternberg cells
• Non-Hodgkin lymphoma

image Follicular, small, cleaved cells (most common)
image Small, noncleaved cells (Burkitt lymphoma [rare])

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image Asymptomatic, RUQ pain, tender hepatomegaly
image Weight loss, jaundice, or ascites
• Lab data: Elevated liver function tests; normal in 25-50% of patients
• Diagnosis: Imaging, core biopsy, and FNA

Demographics

• Age

image Usually middle-aged or older
• Epidemiology

image > 50,000 deaths per year in USA due to liver metastases from colorectal cancer alone

Natural History & Prognosis

• Depends on primary tumor site
• 20-40% have good 5-year survival rate if resectable
• Resection plus chemotherapy offers excellent 5- and 10-year survival in selected patients

Treatment

• Resection or ablation for colorectal liver metastases
• Chemo- or radioembolization for hypervascular (carcinoid or endocrine) metastases
• Chemotherapy (oral or IV) for all others

DIAGNOSTIC CHECKLIST

Consider

• Multifocal, benign lesions (cysts, hemangiomas, &/or focal nodular hyperplasia)

Image Interpretation Pearls

• In absence of known primary tumor or other metastases

image Hepatic lesions that are “too small to characterize” rarely represent metastases
image Lesions that are lower than blood density on NECT rarely represent metastases
image
(Left) Ultrasound of a 60-year-old woman with a pancreatic endocrine tumor shows an echogenic mass image near the confluence of hepatic veins that mimics the appearance of a hemangioma.

image
(Right) Axial, venous phase CECT shows the same mass image having the typical appearance of a metastasis, rather than a hemangioma. In an oncology patient, sonography is generally less reliable than CT or MR in detection and characterization of solid masses, though exceptions do occur.
image
(Left) Axial arterial phase CECT in a patient with a metastatic carcinoid tumor shows a hypervascular metastasis image adjacent to the IVC.

image
(Right) Axial portal venous CECT in the same patient shows the mass image as nearly isodense to the liver and difficult to recognize. For hypervascular tumors, it is critical to obtain both arterial and venous phase images through the liver. Hypervascular tumors include primary HCC and adenomas; metastatic endocrine, renal, thyroid; and some melanoma sarcoma, and breast cancers.
image
(Left) Axial CECT in a patient with a metastatic gastric GIST shows a heterogeneous soft tissue density metastasis image.

image
(Right) Axial CECT in the same patient following treatment shows the metastasis as a near-water-density cystic mass image, which could be mistaken for a simple cyst. Cystic metastases can result from a variety of primary tumors, especially sarcomas and cystadenocarcinomas of the ovary. Attention to details such as mural nodularity and comparison with prior imaging studies are key.
image
(Left) Axial T1WI MR in a patient with metastatic melanoma shows multiple metastases image that have the peculiar feature of being hyperintense on T1WI, which is attributed to the melanin in these lesions. Most metastases are hypo- or isointense to the liver on T1WI.

image
(Right) Axial T2WI MR in the same patient shows the metastases image, but they are nearly isointense to the liver except for foci of necrosis that are hyperintense image.
image
(Left) Axial NECT in a patient with calcified metastases from colorectal cancer shows 1 of several calcified focal liver metastases image.

image
(Right) Axial portal venous CECT in the same patient shows many more metastases image. The calcification is more difficult to recognize on this phase of CECT. Calcified metastases can result from several primary tumors, especially mucinous adenocarcinomas of the colon and ovary.
image
(Left) Axial CECT in a patient with metastatic breast cancer shows a dysmorphic liver with a lobulated and nodular contour image. The presence of subtle hypodense lesions image within the liver indicates widespread metastases. In response to chemotherapy, some have shrunk in size and become fibrotic, resulting in the appearance of pseudocirrhosis.

image
(Right) More caudal section in the same patient shows the pseudocirrhosis pattern with widened fissures and peripheral nodularity with capsular retraction image.
image
(Left) Axial T2WI of a 44-year-old man with colon cancer showed a total of 4 metastases image, 3 of which are seen on this section.

image
(Right) T1WI MR images obtained 20 minutes after the IV administration of gadoxetate (Eovist) revealed at least 3 additional metastases image. Gadoxetate can make small metastases much more evident than on routine MR or CT evaluation. In this patient, the presence of 6 metastases precluded surgical or ablative therapy.
image
(Left) Axial NECT in a patient with metastatic breast cancer shows an enlarged low-attenuation liver that might be misinterpreted as steatosis.

image
(Right) Axial CECT in the same patient shows innumerable hypervascular liver metastases image. Ascites is also present. Diffuse metastases that simulate hepatic steatosis can be seen with a variety of primary tumors, including breast, melanoma, and especially lymphoma.
image
(Left) Axial CECT of a 59-year-old woman with breast cancer and liver disfunction shows poorly defined low density image replacing most of the right lobe of the liver, in a pattern suggesting steatosis or widespread metastases.

image
(Right) One week later, a PET/CT scan was performed. Axial fused PET/CT images show that the abnormal portions of the liver image are FDG avid, indicating malignant disease (metastases). PET/CT can be valuable in detection of subtle or diffuse liver metastases or lymphoma.
image
(Left) Axial NECT in a patient with metastatic melanoma shows subtle hypodense metastases image and others that are hyperdense image. Melanoma is one of the few metastases that may be hyperdense to normal-attenuation liver; almost any metastases can be hyperdense to fatty liver.

image
(Right) Axial CECT in a patient with spontaneous bleeding shows a sentinel clot image adjacent to a liver mass image, indicating this as the source of bleeding. Also note hemoperitoneum image, a relatively rare complication of liver metastases.
image
(Left) Axial T1WI C+ MR in a patient with hepatic lymphoma shows a large, heterogeneously hypointense mass image.

image
(Right) Axial T2WI FS MR in the same patient shows that the large solitary mass is heterogeneously hyperintense image.
image
(Left) Axial CECT in a patient with diffuse hepatic lymphoma shows innumerable small foci of tumor in the liver and spleen. On NECT, the liver appeared diffusely enlarged and low in attenuation, resembling benign steatosis.

image
(Right) Axial CECT in a patient with NHL and AIDS shows multifocal hypodense masses image in the liver and spleen. Similar masses were present in the kidneys and in multiple nodal groups. AIDS patients and transplant recipients are at high risk for developing non-Hodgkin lymphoma.
image
(Left) Axial CECT of a 60-year-old man with melanoma and abnormal liver function shows that the liver is enlarged and diffusely decreased in attenuation, consistent with diffuse tumor or steatosis. Subtle focal hypodense lesions image are also seen.

image
(Right) CECT section in the same patient shows more of the diffusely low-attenuation liver.
image
(Left) Additional focal hypodense lesions are seen image, but these are still consistent with focal steatosis or metastases.

image
(Right) Longitudinal sonogram shows innumerable hypoechoic lesions image, many of them are < 1 cm in diameter. Focal steatosis would be echogenic; therefore, these lesions are likely to represent metastases (proven on biopsy).
image
(Left) Another longitudinal US image shows more of the innumerable hypoechoic metastases, many more than suggested by CT.

image
(Right) Color Doppler US shows vascularity within and around some of the metastases.
image
Axial CECT shows multiple colorectal metastases having a typical target appearance image. Note the obstruction of intrahepatic bile ducts image.

image
Axial T1WI C+ MR shows a large heterogeneous hypointense mass that proved to be metastatic colon cancer.
image
Axial T2WI MR shows heterogeneous intensity within the metastatic mass (colon primary) and hyperintensity of surrounding parenchyma, perhaps due to edema &/or compression of liver.
image
Axial CECT shows multiple hypodense masses, some almost isodense to liver, in a patient with AIDS and diffuse lymphoma.
image
Axial CECT shows necrotic metastasis with a shaggy enhancing wall causing extrinsic compression and obstruction of the left lobe bile ducts. The mass proved to be metastatic colon carcinoma.
image
Axial T2WI MR shows bright signal (light bulb sign) in the center of 2 cystic/necrotic metastases from sarcoma of the gastrointestinal tract.
image
Axial NECT shows several focal masses with amorphous calcification, characteristic of mucinous adenocarcinoma (colon primary).

Share this: