Diagnostic ultrasound ( PDFDrive )

116 PART II Abdominal and Pelvic Sonography
in association with GSD. In particular, the frequency of adenoma
for type 1 GSD (von Gierke disease) is 40%. 163 Because of its
propensity to hemorrhage and risk of malignant degeneration, 162
surgical resection is recommended. he genotyping/phenotyping
of hepatic adenomas reveals three major subtypes, with the ability
to predict also those with malignant potential on the basis of
the tumor phenotype, with β-catenin–activated adenomas at
higher risk of HCC. 164
Pathologically, a hepatic adenoma is usually solitary, 8 to
15 cm, and well encapsulated. Microscopically, the tumor consists
of normal or slightly atypical hepatocytes. Bile ducts and Kupfer
cells are few or absent. Hepatic adenomas may show either
calciication or fat (Figs. 4.50 and 4.51), both of which appear
echogenic on sonography, making their gray-scale appearance
suggestive in some cases.
Diferentiation of hepatic adenomas from FNH is oten not
possible by their gray-scale or Doppler characteristics. Further,
both have a similar demographic, occurring in young women
in their childbearing years, oten with a history of oral contraceptive
use. Most adenomas are cold on technetium-99m sulfur
colloid imaging as a result of absent or greatly decreased numbers
of Kupfer cells. Isolated cases of radiocolloid uptake by the
adenoma have been reported. 165 Today, MRI is a frequently used
modality for the characterization of adenomas. 166
In the typical clinical scenario, diferentiation of FNH from
adenoma poses a regular problem. Both masses are frequently
incidentally detected in asymptomatic women, their baseline
appearance at sonography is variable, and both produce a
hypervascular mass in the arterial phase on contrast CT or MRI. 167
heir management are totally diferent. However, diferentiation
A
B
FIG. 4.50 Hepatic Adenoma. (A) Sonogram, and (B) conirmatory computed tomography (CT) scan, show a large exophytic liver mass in an
asymptomatic young woman. The mass shows highly echogenic foci, which correspond to areas of fat and calciication on the CT scan.
A
B
FIG. 4.51 Hepatic Adenoma: Gray-Scale Appearances in Two Patients. (A) Sagittal sonogram of the left lobe of the liver of an asymptomatic
35-year-old man shows a highly echogenic mass. It is unusual to see an adenoma in an otherwise normal man. (B) Oblique sonogram of a 26-year-old
Chinese woman shows a highly echogenic mass with a hypoechoic halo. The hypoechoic halo was related to a surrounding zone of liver atrophy
on biopsy. These highly echogenic masses show diffuse steatosis and are, therefore, HNF1a-inactivated adenomas.