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PATHOLOGY OF THE LIVER AND PORTAL VENOUS SYSTEM 81
Figure 4.3 Large, infected hepatic cyst containing lowlevel
echoes.
Another uncommon cause of a cystic lesion in the
liver is a cystadenoma—a benign epithelial tumour.
These have the potential to turn malignant, forming
a cystadenocarcinoma. Close monitoring with ultrasound
will demonstrate a gradual increase in size,
changes in the appearances of the wall of the cyst,
such as thickening or papillary projections, and
internal echoes in some cases, which may arouse
suspicion. A diagnostic aspiration may be performed
under ultrasound guidance, and the fluid may contain
elevated levels of carcinoembryonic antigen if
malignant. 2 Cystadenomas are usually surgically
removed due to their malignant potential (Fig. 4.4).
Rarely, cystic lesions in the liver may be due to
other causes. These include pancreatic pseudocyst
(within an interlobular fissure) in patients with
acute pancreatitis or mucin-filled metastatic
deposits in primary ovarian cancer.
An arteriovenous malformation, a rare finding
in the liver, may look like a septated cystic lesion.
Doppler, however, will demonstrate flow throughout
the structure.
Polycystic liver
There is a fine dividing line between a liver which
contains multiple simple cysts and polycystic liver
A
B
Figure 4.4 (A) Large cystadenoma containing echoes and a septum. The cyst was large enough to cause obstructive
jaundice—the patient’s presenting symptom. The diagnosis was made by ultrasound-guided aspiration. This cyst had
developed into a cystadenocarcinoma after 2 years. (B) A cystadenocarcinoma in a young woman presenting with
altered liver function tests (LFTs). The cyst contains echoes and some solid material.