Type:
Educational Exhibit
Keywords:
Neoplasia, Education, MR, CT, Oncology, Liver, Abdomen
Authors:
P. H. D. Silva1, F. Velloni1, H. R. F. Dalla Pria1, S. L. Haiek2, F. Tamamoto1, L. F. D. Silva1, R. A. Santiago1, U. S. Torres1, G. D'Ippolito1; 1São Paulo/BR, 2Sao Paulo /BR
DOI:
10.1594/ecr2018/C-1134
Background
HCC is the leading primary malignant neoplasm of the liver and the fifth most common neoplasm in the world.
Because its poor prognosis,
it is the second leading cause of cancer death in men.
Risk factors for HCC include chronic viral hepatitis (specially B and C viruses types),
alcohol,
liver cirrhosis,
exposure to hepatotoxins,
obesity,
type 2 diabetes,
non-alcoholic fatty liver disease (associated with obesity),
and smoking.
Due to the high prevalence of these risk factors,
the impact of HCC on global health is expected to increase in the next years.
The use of ultrasound and alpha-fetoprotein (AFP) in HCC screening are well established for its early detection,
and may lead to further investigation,
if necessary.
In the context of chronic liver disease,
HCC can be diagnosed exclusively by means of three-phase contrast-enhanced computed tomography (CT) and/or magnetic resonance imaging (MRI),
as long as the lesion presents a typical enhancement pattern,
which excludes the necessity of further investigation (i.e.
invasive histopathological confirmation): arterial hyperenhancement with washout in the portal venous and delayed phases.
This typical pattern is seen in approximately 60% of HCC lesions.
HCC usually presents homogeneous or discretely heterogeneous attenuation in non-enhanced CT,
as well as in contrast-enhanced phases.
On MRI,
it shows a slight hyperintense signal in T2-weighted (T2-W) sequences and slight hyperintense signal in T1-W sequences (both sometimes heterogeneous),
as well as absence of fatty components.
However,
atypical presentation patterns may occur,
and the isolated evaluation of the enhancement pattern may be therefore insufficient.
Radiologists must recognize the main imaging features related to atypical HCC since early diagnosis may change management and improve prognosis.