Submitted by Matt
Hoffman, MD
·
Hemangiomas are the
most common benign
hepatic neoplasm
·
Incidence of
approximately 20%
·
Occur
more commonly in women
·
These
lesions tend to be
stable, though may
enlarge during
pregnancy or with
estrogen
administration
·
Clinical findings
o
Usually
asymptomatic and
discovered
incidentally
o
Large
lesions may cause
pain, nausea, or
vomiting secondary to
extrinsic compression
of adjacent bowel,
rupture, hemorrhage,
or thrombosis
o
Large
hemangiomas may
sequester platelets
and produce
thrombocytopenia and
DIC, a condition know
as Kasabach-Merritt
syndrome
·
Histopathology
o
Hemangiomas are
composed of large
vascular channels
filled with slowly
moving blood and are
lined by a single
layer of endothelial
cells
o
Giant
hemangiomas (measuring
greater than 6 cm) can
contain hemorrhage,
thrombus,
calcification, or
fibrosis
o
Larger
lesions are less
common, comprising
less than 10% of all
hemangiomas
·
Imaging
o
Since
hemangiomas are often
detected incidentally,
the importance of
imaging lies in the
fact that they must be
differentiated from
more clinically
significant lesions,
such as primary and
secondary hepatic
malignancies
·
Ultrasound
o
Usually
homogeneous
o
Well-defined
hyperechoic masses
(though few can appear
relatively hypoechoic
when imaged within a
fatty liver)
o
Giant
lesions can appear
heterogeneous
secondary to internal
complex composition
o
Posterior acoustic
enhancement is
commonly seen
·
Nuclear Imaging
o
On
99mTc-sulfur colloid
scintigraphy,
hemangiomas appear as
focal photopenic areas
o
99mTc-pertechnetate-labeled
RBC SPECT is a more
specific examination
§
Early
dynamic images yield
focal photopenic areas
that gradually
increase in activity
over time
§
Limited
utility for lesions
smaller than 2-3cm due
to poor spatial
resolution
·
CT
o
Focal,
well-circumscribed,
low attenuation
lesions on
pre-contrast images
o
Nodular,
peripheral centripetal
enhancement on dynamic
contrast enhanced
imaging
·
MRI
o
Has a
sensitivity and
specificity of greater
than 90% and is the
imaging modality of
choice
o
Typically hemangiomas
are homogeneously
hypointense relative
to the liver on
T1-weighted and
markedly hyperintense
(lightbulb sign) on
T2-weighted images
relative to the liver
o
On
dynamic,
contrast-enhanced MR
imaging, hemangiomas
can demonstrate
immediate homogeneous
enhancement (lesions <
1.5cm)
o
Peripheral, nodular
centripetal
enhancement pattern
progressing to
homogeneity (lesions
1.5-5cm)
o
Peripheral nodular
centripetal
enhancement with
persistent central
hypointense region
(lesions> 5cm)
Giant cavernous
hemangioma of the
liver:
Axial T1-weighted
pre-contrast
image
shows a
hypointense mass
within the right
hepatic lobe.
Sequential enhanced
delayed images show
peripheral nodular
centripetal
enhancement with
persistent central
hypointensity
For a static Image of
this Case, Click Here
o
Giant
hemangiomas often do
not achieve complete
isointensity on
delayed images due to
their complex internal
composition
§
These
larger lesions still
should demonstrate the
characteristic
peripheral nodular
enhancement
§
MRI
appearance is that of
a well-defined,
heterogeneous mass
with areas of bright
signal on T2-weighted
images, cleft-like
areas of low intensity
on T1, and low
intensity internal
septae on all pulse
sequences
