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PATHOLOGY OF THE LIVER AND PORTAL VENOUS SYSTEM 91
acterize the primary source by the acoustic properties
of the metastases.
Metastases tend to be solid with ill-defined margins.
Some metastases, particularly the larger ones,
contain fluid as a result of central necrosis (Fig.
4.16E), or because they contain mucin, for example
from some ovarian primaries. Occasionally, calcification
is seen within a deposit, causing distal
acoustic shadowing, and this may also develop following
treatment with chemotherapy.
In some diseases, for example lymphoma, the
metastases may be multiple but tiny, not immediately
obvious to the operator as discrete focal
lesions but as a coarse-textured liver (Fig. 4.16F).
This type of appearance is non-specific and could
be associated with a number of conditions, both
benign and malignant.
Diagnosis of focal liver lesions, such as metastases,
is made more difficult when the liver texture
is diffusely abnormal or when there are dilated
intrahepatic ducts because the altered transmission
of sound through the liver masks small lesions.
Other possible ultrasound features associated with
metastases include a lobulated outline to the liver,
hepatomegaly and ascites.
If the finding of liver metastases is unexpected,
or the primary has not been identified, it is useful
to complete a full examination to search for a
A
B
C
D
Figure 4.16 Examples of liver metastases. (A) Peripheral secondary deposits due to peritoneal spread from a primary
ovarian carcinoma. (B) Blood-borne metastases from bowel carcinoma are demonstrated in the central area of the liver
around the porta. (C) Solitary ‘target’ metastasis. (D) Large hyperechoic metastasis occupying most of the right lobe
and causing an obvious mass effect.
(Continued)