Liver Diseases
Benign Liver Tumors
Benign Liver Tumors
• Benign liver tumors are relatively common but usually subclinical.
• Most are detected incidentally by ultrasound (US) or other scanning
techniques.
• Others are discovered because of hepatomegaly, right upper
quadrant discomfort, or intraperitoneal hemorrhage.
• Liver function tests are usually normal
The most important benign tumor of the liver are cavernous
hemangioma, focal nodular hyperplasia (FNH) and
hepatocellular adenoma (HA, liver cell adenoma – LCA).
Cavernous Hemangioma
Cavernous Hemangioma
Cavernous hemangioma is the
most common primary liver
tumor; its occurrence in the
general population ranges from
0.4-20%.
Cavernous hemangioma is a benign connective tissue tumor resulted from
endothelial cells proliferation.
It is a non-encapsulated tumor, with an infiltrative, lobular growing. The tumor
consists of large (cavernous) spaces, lined by tumor endothelial cells
Cavernous Hemangioma
• Usually, they occur as solitary lesions.
• However, they may be multiple in as many as 50% of patients.
• Hemangiomas typically measure less than 5 cm; some authors call those
larger than 4-5 cm giant hemangiomas.
Hemangioma showing characteristic sharp demarcation
from the surrounding liver and "spongy" texture.
Cavernous Hemangioma
• The vast majority of hemangiomas (as many as 85%) are
asymptomatic.
• Because of advances in imaging technology, hemangiomas are
being detected more frequently.
• Hemangiomas may cause symptoms because of the compression of
adjacent structures, acute thrombosis, or consumptive
coagulopathy (Kasabach-Merritt syndrome - giant hemangiomas).
• Spontaneous or posttraumatic rupture is a catastrophic
complication that occurs in about 1-4% of hemangiomas; it has a
considerable mortality rate, as high as 60%
Cavernous Hemangioma
The classic diagnostic findings for hemangioma are as follows:
• on unenhanced CT, hypoattenuation similar to that of vessels;
• on dynamic contrast-enhanced CT or MR imaging, peripheral globular
enhancement and a centripetal fill-in pattern with the attenuation of
enhancing areas identical to that of the aorta and blood pool;
• on T2- and heavily T2-weighted MR imaging, hyperintensity similar to that
of cerebrospinal fluid;
• on sonography, homogeneous hyperechogenicity or hypo- or
isoechogenicity with a hyperechoic rim;
• on delayed phases of 99mTc RBC scanning, a defect in the early
phases that shows prolonged and persistent filling-in.
From: Gore RM, Levine MS. Textbook of gastrointestinal radiology, 2nd ed. Philadelphia: Saunders, 2000: 1487-1497
Cavernous Hemangioma
CT Findings:
• Hemangiomas are
enhancing lesions that
have characteristic
dynamic features after the
administration of contrast
material.
• On nonenhanced CT
scans, hemangiomas
appear hypoattenuating
relative to the adjacent
liver.
CT of the liver following intravenous contrast medium administration at
20 sec, at 40 sec, at 1 minute and at 3 minutes, respectively. Early
clear enhancement of peripheral vascular lakes is rapidly followed by
progressive opacification of the central portions of the haemangioma.
At 3 minutes following contrast injection the whole lesion is markedly
enhanced relative to the liver.
• During the arterialdominant phase, small
hemangiomas show
intense and uniform
contrast enhancement
and retain their contrast
enhancement during the
portal venous phase
Cavernous Hemangioma
CT Findings:
0’’
30’’
The pattern of a peripheral,
discontinuous, intense
nodular enhancement
during the arterial-dominant
phase with progressive
centripetal fill-in is
considered pathognomic
for hemangiomas
1’
15’
Contrast-enhanced CT scans
reveal the pathognomic features
of a hemangioma, namely,
peripheral nodular
enhancement and progressive
centripetal fill-in (arrow).
Cavernous Hemangioma
Ultrasound
At ultrasonography,
hemangiomas appear as
well-circumscribed,
uniformly hyperechoic
lesions
Cavernous Hemangioma
Ultrasound
• Atypical features include hypoechoic
lesions with a thin hyperechoic rim or a
thick rind and scalloped borders
• Hemangiomas may appear hypoechoic
in fatty livers
Cavernous Hemangioma
MRI Findings:
• MRI is more sensitive and specific than other imaging modalities in the diagnosis of
hemangiomas.
• Hemangiomas appear as smooth, lobulated, homogeneous, hypointense lesions on T1weighted images.
• On T2-weighted images, they appear hyperintense relative to liver. The high signal intensity on
T2-weighted images is due to the extremely long T2 relaxation time of the free fluid (slowly
moving blood)
Cavernous Hemangioma
MRI Findings:
With the injection of contrast material (gadolinium chelates), lesions typically
demonstrate peripheral nodular enhancement with progressive, centripetal
fill-in that usually appears after 5-30 minutes
Cavernous Hemangioma
Angiography
• Angiography has been used extensively in
the past as the gold standard to
characterize CH but is not applied any
more for this purpose due to the several
noninvasive imaging methods now
available.
• It is, however, important to know the
angiographic features of this very common
hepatic lesion because it may be
displayed on hepatic arteriograms
performed for other purposes.
Angiography of the hepatic artery, arterial phase.
Multiple nodular contrast accumulations in Cshaped configuration.
Focal Nodular Hyperplasia
Focal Nodular Hyperplasia
Focal nodular hyperplasia (FNH) is the second most common
tumor of the liver and constitutes 8% of all liver tumors
• FNH occurs predominantly in women
(80 - 90%) during the third to fifth
decade.
• FNH is not a true neoplasm, and it is
believed to represent a hyperplastic
response to increased blood flow in an
intrahepatic arteriovenous
malformation.
• Kupffer cells are usually present in the
lesion
• Most cases of FNH occur as a solitary
lesion (80-95%)
Focal Nodular Hyperplasia
• FNH is normally a solitary, lobulated,
nonencapsulated tumour of relatively
small size; usually less than 5 cm in
diameter.
• It is frequently located in the
subcapsular areas of the liver and
may be pedunculated.
• FNH frequently displays a central
fibrous structure or "scar" with
multiple radiating fibrous septa.
Typically this scar is strongly
vascularized by branches coming
from the hepatic artery.
A classic focal nodular hyperplasia,
paler than the surrounding liver, and
with a distinct central stellate scar.
Focal Nodular Hyperplasia
• In most patients, FNH is discovered incidentally during imaging or laparotomy
for unrelated conditions. Most patients are asymptomatic.
• A small minority (10-15%) may present with vague abdominal symptoms from
mass effect, a palpable mass, or hepatomegaly.
• The most common complication of FNH is hemorrhage observed in only 2-3%
Although FNH usually has no clinical significance, recognition of
the radiological characteristics of FNH is important to avoid
unnecessary surgery, biopsy, and follow-up imaging.
Focal Nodular Hyperplasia
The imaging modalities that can best characterize FNH are those
that can delineate the central scar or show Kupffer-cell activity:
• US, particularly when combined with duplex Doppler US, may be
the only type of imaging required.
• CT and MRI demonstrate the central scar best, whereas
radionuclide scans best demonstrate Kupffer-cell activity.
• The introduction of MRI superparamagnetic contrast agents may
challenge the role of radionuclide scanning in the future.
Focal Nodular Hyperplasia
Ultrasound
• For imaging of the right upper quadrant, ultrasonography (US) is more
widely used than other modalities, and usually, US findings raise the
possibility of FNH.
There is a large (diameter 9 cm)
area with iso- or slightly
hyperechoic pattern in the left
liver lobe. The lesion is bordered
by a hyperreflective rim.
Focal Nodular Hyperplasia
Ultrasound
Doppler ultrasound shows centrifugal arterial flow originating from the
central portion of the lesion or sometimes from a central vessel with a
stellate configuration.
Focal Nodular Hyperplasia
CT Findings:
Typical CT finding of a FNH:
• In the native scan this benign
tumor appears to be almost
isodense to the surrounding liver
tissue; in its center a "scar" of
lower density can be seen
distinctly (top left image).
• 25 secs after contrast agent
application, enhancement starts
(top middle image), reaching its
maximum after 30-40 secs (top
right image). Note the typical
delicate structure of the
hypodense septae, which
appear in a radial order.
• After 45-60 secs, homogenous
contrasting is reached (bottom
left image); this is followed by a
gradual decay in contrasting.
Focal Nodular Hyperplasia
MRI Findings:
• FNH usually has homogeneous signal intensity on MRIs.
• The lesion is isointense to hypointense on T1-weighted images in
94-100% of patients.
• On T2-weighted images, the lesion is slightly hyperintense to
isointense in 94-100% of patients.
• The central scar is hypointense on T1-weighted images, but it
shows a variable signal-intensity pattern on T2-weighted images.
Focal Nodular Hyperplasia
MRI Findings:
T1-weighted sequence.
T2-weighted sequence.
A focal lesion (arrow) with a
diameter of 2.5 cm is hypointense
relative to the liver parenchyma.
The lesion is slightly and
inhomogeneously hyperintense.
Focal Nodular Hyperplasia
MRI Findings:
If a hepatic mass contains a
low signal central scar on
T1-weighted images that
enhances after gadolinium
administration, the
diagnosis of FNH is fairly
certain.
Contrast-enhanced T1-weighted MR
image, obtained 4 min after injection,
shows that lesion remains slightly
hyperintense to normal liver, but
central scar is highly enhanced
(arrowhead).
Focal Nodular Hyperplasia
Nuclear Scintigraphy :
Hepatobiliary scintigraphy (performed with Tc-99m HIDA or an analogue) is
useful in diagnosing focal nodular hyperplasia – it may show normal-to-increased
uptake in 40-70% of patients.
"hot spot"
In the early phase, the
activity is low.
In the late phase, a large area of
increased residual activity marks
the FNH in the right lobe.
Hepatocellular Adenoma
Hepatocellular Adenoma
Hepatocellular adenoma (HA) is a rare benign tumor of the liver. Two types of
HAs have been identified, including tumors of bile duct origin and tumors of
liver cell origin:
1. HAs of bile duct origin usually are smaller than 1 cm and not of clinical
interest; typically, they are found incidentally on postmortem examinations.
2. HAs of liver origin are larger and often are clinically significant. On average,
they measure 8-15 cm.
Hepatocellular Adenoma
HA is the most important benign tumor of the liver.
• Although HAs may be idiopathic, the lesions most often are seen in
young women using oral contraceptives.
(The incidence among long-term users of oral contraceptives is approximately 4 cases per
100,000. In women who do not use oral contraceptives or have used them for less than 2
years, the incidence is 1 case per million)
• HAs may rupture and bleed, causing right upper quadrant pain.
(Rarely, rupture may lead to hemorrhagic shock)
• HA may undergo malignant degeneration.
(Even at histopathological study it may be difficult to differentiate adenoma from well
differentiated hepatocellular carcinoma)
Surgical resection is advocated in most
patients with presumed HAs.
Hepatocellular Adenoma
Most adenomas are not specifically diagnosed at US and are usually further
evaluated with CT or other imaging modalities.
• Color Doppler US may help differentiate HA from FHN.
• Multiphasic helical CT allows more accurate detection and characterization
of focal hepatic lesions.
• HAs are typically bright on T1-weighted magnetic resonance images and
predominantly hyperintense relative to liver on T2-weighted images.
• Findings at radionuclide scintigraphy are rarely diagnostic for HA
Understanding the imaging appearance of HAs can help avoid misdiagnosis
and facilitate prompt, effective treatment.
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
Ultrasound
• On US, HAs demonstrate variable echogenicity.
• The most adenomas are not specifically diagnosed at US and are usually further
evaluated with CT or other imaging modalities.
Sagittal US scan of the liver shows a welldefined, homogeneous, hyperechoic lesion in the
right lobe (arrow).
Transverse US scan of the liver shows a
hypoechoic lesion (cursors) with a hyperechoic
center (arrow) due to recent hemorrhage.
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
Ultrasound
Color Doppler US may
demonstrate:
• peripheral peritumoral
vessels and
• intratumoral vessels
that typically have a flat
continuous waveform.
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
CT Findings:
A multiphasic CT scan should be performed to better characterize
most hepatic tumors.
• On CT, the most consistent finding in HAs is the enhancement pattern.
Most lesions show homogeneous enhancement in the hepatic arterial phase.
(Unfortunately, this feature is not specific to HAs, since HCC, hypervascular metastases, and
FNH can demonstrate similar enhancement in the hepatic arterial phase.)
• Since HAs are composed histologically of uniform hepatocytes, most are
isoattenuating to healthy liver tissue on nonenhanced scans in the portal
venous phase.
• The finding of hemorrhage as an area of high attenuation can be seen in
as many as 40% of patients.
• Typically, HAs have well-defined borders and do not have lobulated contours.
• A low-attenuation pseudocapsule can be seen in as many as 25% of patients.
Hepatocellular Adenoma
CT Findings:
Arterial-phase CT scan shows multiple
hypervascular lesions (arrows).
On a portal venous-phase CT scan, the
adenomas are isoattenuating relative to
the surrounding parenchyma.
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
CT Findings:
Unenhanced CT
scan shows a
hypoattenuating
lesion with highattenuation blood
centrally (arrow).
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
MRI Findings:
Some MRI findings are similar to CT findings; however, MRI usually is more
sensitive in detecting fat and hemorrhage.
• HAs tend to be hyperintense or isointense to liver tissue on T1-weighted
images
(Other hepatic lesions can be hyperintense on T1-weighted images, such as melanoma
metastases and cavities containing proteinaceous material)
• On T2-weighted images, HAs most often are slightly hyperintense to liver
tissue.
(This finding is not specific since many hepatic lesions, including HCC and metastases, are
hyperintense on T2-weighted images)
• After gadolinium administration, the pattern of enhancement is similar to
that of CT.
(Most HAs show intense enhancement in the arterial phase and are isointense to liver tissue
on delayed imaging)
• A central scar has never been reported in an HA.
Hepatocellular Adenoma
MRI Findings:
a
b
(a) Portal venous-phase CT scan shows a poorly
enhancing, spheric mass without obvious hemorrhage.
(b) On a T2-weighted MR image, the mass appears
heterogeneously hyperintense.
(c) T1-weighted MR image shows the mass with
heterogeneous hyperintensity due to hemorrhage.
c
From: Luigi Grazioli et al. Hepatic Adenomas: Imaging and Pathologic Findings Radiographics. 2001;21:877-892.
Hepatocellular Adenoma
MRI Findings:
Large HCC with a mosaic
pattern, a tumor capsule, and
fatty infiltration.
Axial fat-saturated delayed
contrast-enhanced MR image
shows enhancement of a
tumor capsule (arrow).
On routine MRI of the liver consisting of T1-weighted and T2-weighted
images, chemical-shift imaging, and dynamic gadolinium-enhanced imaging,
distinguishing between HAs, HCC, and hypervascular metastases usually is
not possible.
Hepatic Cyst
Hepatic Cyst
• The term hepatic cyst usually refers to solitary nonparasitic cysts of the liver,
also known as simple cysts. Most patients with simple cysts are asymptomatic
and require no treatment.
• The precise frequency of liver cysts is not known because most do not cause
symptoms, but liver cysts have been estimated to occur in 5% of the population.
• The cause of simple liver cysts is unknown, but cysts are believed to be
congenital in origin.
• Hepatic cysts are not neoplasms.
(The pathophysiology of simple hepatic cysts is related to fluid secretion by the epithelial
lining. Typically, the fluid within the cyst has an electrolyte composition that mimics plasma)
The clinician has a number of options for imaging the liver in patients with
hepatic cysts.
A practical problem in the evaluation of a patient with a cystic hepatic
lesion is differentiating cystic neoplasms from simple cysts.
Hepatic Cyst
Simple cysts tend to have
homogenous low-density interiors
The margin of the cystic lesion is well
defined and the cyst wall is thin and
smooth.