Diagnostic ultrasound ( PDFDrive )

CHAPTER 4 The Liver 83
A
B
FIG. 4.14 Biliary Cystadenoma. (A) Sagittal sonogram shows irregular liver cyst with thick septa and mural nodules. (B) Surgical specimen.
Pathologically, peribiliary cysts are believed to represent small,
obstructed periductal glands. Sonographically, they may be seen
as discrete, clustered cysts or as tubular-appearing structures
with thin septae, paralleling the bile ducts and portal veins.
Autosomal Dominant Polycystic Disease
Autosomal dominant polycystic kidney disease has liver cysts
in 57% to 74% of patients. 18 No correlation exists between the
severity of the renal disease and the extent of liver involvement.
Results of LFTs are usually normal and, unlike the autosomal
recessive form of polycystic kidney disease, there is no association
with hepatic ibrosis or portal hypertension. Indeed, if LFT results
are abnormal, complications of polycystic liver disease, such as
tumor, cyst infection, and biliary obstruction, should be
excluded. 18
Biliary Hamartomas (von Meyenburg
Complexes)
Bile duct hamartomas, irst described by von Meyenburg in 1918,
are small, focal developmental lesions of the liver composed of
groups of dilated intrahepatic bile ducts set within a dense collagenous
stroma. 19 hese benign liver malformations are detected
incidentally in 0.6% to 5.6% of autopsy series. 20
Imaging features of von Meyenburg complexes (VMCs) 21
include single, multiple, or, most oten, innumerable welldeined
solid nodules usually less than 1 cm in diameter (Fig.
4.15). Nodules are usually uniformly hypoechoic 21 and less
frequently hyperechoic on sonography 22,23 and hypodense on
contrast-enhanced computed tomography (CECT) scan. Because
of their multiplicity they can be confused with metastatic cancer.
Bright echogenic foci in the liver with distal comet tail artifact
without obvious mass efect are key sonographic indings
(Fig. 4.16). We believe that these echogenic foci could be
related to the presence of tiny cysts beyond the resolution of the
ultrasound equipment. VMCs are usually isolated, insigniicant
observations and may occur with other congenital disorders,
such as congenital hepatic ibrosis and polycystic kidney or liver
disease. 20 Association of VMCs with cholangiocarcinoma has been
suggested. 24
FIG. 4.15 Von Meyenburg Complex in Cancer Patient. Sonogram
shows a single, small, hypoechoic liver mass. With no other evidence
of metastatic disease, a biopsy was performed and proved the benign,
insigniicant nature of this lesion.
INFECTIOUS DISEASES
Viral Hepatitis
Viral hepatitis is a common disease that occurs worldwide. It is
responsible for millions of deaths secondary to acute hepatic
necrosis or chronic hepatitis, which in turn may lead to portal
hypertension, cirrhosis, and hepatocellular carcinoma (HCC).
here are ive distinct hepatitis viruses: hepatitis A through E.
Other viruses cause hepatitis, but these are the classically characterized
ones.
Hepatitis A occurs throughout the world and can be diagnosed
using serosurveys with the antibody to hepatitis A virus (anti-
HAV) as the marker. he primary mode of spread is the fecal-oral
route. In developing countries the disease is endemic and infection
occurs early in life. Hepatitis A is an acute infection leading to
complete recovery or death from acute liver failure.
Hepatitis B is transmitted parenterally (e.g., blood transfusions,
needle punctures) as well as by nonpercutaneous exposure through