Approach Considerations
The evaluation of a patient with a simple liver cyst involves carefully recording the patient history and performing a physical examination plus an imaging study (eg, abdominal computed tomography [CT]) to define the anatomy of the cyst. The clinician can minimize the cost of evaluation by obtaining only key studies that may alter the treatment plan.
Before the widespread availability of abdominal imaging techniques, including ultrasonography and CT, liver cysts were diagnosed only when they grew to an enormous size and became apparent as an abdominal mass or as an incidental finding during laparotomy. Today, imaging studies often reveal asymptomatic lesions incidentally.
Laboratory Studies
Little preoperative laboratory workup is required for these patients. Liver function test (LFT) results, such as transaminases or alkaline phosphatase, may be mildly abnormal, but bilirubin, prothrombin time (PT), and activated partial thromboplastin time (aPTT) are usually within the reference range.
In the setting of polycystic liver disease (PCLD), greater abnormalities in LFT results are found, but liver failure is uncommon. Renal function test results, including blood urea nitrogen (BUN) and creatinine levels, are often abnormal and should be performed on initial evaluation.
In the presence of hydatid cysts, eosinophilia is noted in approximately 40% of patients, and echinococcal antibody titers are positive in nearly 80% of patients.
With cystic tumors, as with simple cysts, LFT results are normal. There may be mild abnormalities in some patients. Carbohydrate antigen (CA) 19-9 levels are elevated in some patients. Cyst fluid can be sent for CA 19-9 testing at the time of surgery as a marker for cystadenoma and cystadenocarcinoma.
Patients with hepatic abscesses can usually be easily identified on the basis of the clinical presentation. Leukocytosis is generally present.
The enzyme immunoassay (EIA) test detects specific antibodies to E histolytica.
Imaging Studies
The clinician has a number of options for imaging the liver in patients with hepatic cysts. Ultrasonography is readily available, noninvasive, and highly sensitive. CT (see the image below) is also highly sensitive and is easier for most clinicians to interpret, particularly for treatment planning. Magnetic resonance imaging (MRI), nuclear medicine scanning, and hepatic angiography have a limited role in the evaluation of hepatic cysts.
Simple cysts have a typical radiographic appearance. They are thin-walled with a homogenous low-density interior.
PCLD is confirmed by means of ultrasonography or CT (see the image below), with multiple liver cysts identified at the time initial of evaluation.
Computed tomography (CT) scan of polycystic liver disease curiously limited to right liver.
Hydatid cysts can be identified by the presence of daughter cysts within a thick-walled main cavity (see the image below).
Hepatic cysts. Sagittal magnetic resonance imaging (MRI) reconstruction in patient with large echinococcal cyst; note daughter cysts in interior.
In patients who are jaundiced with hydatid disease, endoscopic retrograde cholangiopancreatography (ERCP) should be performed to determine whether the cyst has ruptured into the bile duct.
Central necrosis of large solid neoplasms can mimic cystic hepatic tumors, in that this area of necrosis appears cystic.
Cystadenoma (see the image below) and cystadenocarcinoma usually appear multiloculated with internal septations, heterogeneous density, and irregularities in the cyst wall. Unlike many tumors, cystadenoma and cystadenocarcinoma are rarely associated with calcifications.
A practical problem in the evaluation of a patient with a cystic hepatic lesion is differentiating cystic neoplasms from simple cysts. Cystic neoplasms tend to have thicker, irregular, hypervascular walls, whereas simple cysts tend to be thin-walled and uniform. Simple cysts tend to have homogenous low-density interiors, whereas neoplastic cysts usually have heterogeneous interiors with septa and papillary extrusions.
Abscesses of the liver appear cystic on imaging studies (see the image below) but can usually be diagnosed from the overall clinical presentation.
Other Tests
Other tests are generally not necessary in the evaluation of hepatic cysts. Percutaneous aspiration should be avoided because the laboratory and cytologic evaluation of the simple cyst fluid is nondiagnostic, and a small risk exists of inducing anaphylaxis from leakage from the hydatid cyst or of causing abscess formation in a previously sterile cyst.
Histologic Findings
Histologic assessment of the excised cyst wall should be routinely undertaken to identify the presence of an unsuspected neoplasm, such as cystadenoma. In simple cysts, histology of the cyst wall generally reveals a layer of simple cuboidal epithelium.
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Histology demonstrating biliary epithelium lining simple cyst.
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Ultrasonographic appearance of large simple hepatic cyst.
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Computed tomography (CT) scan appearance of large hepatic cyst.
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Computed tomography (CT) scan of polycystic liver disease curiously limited to right liver.
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Hepatic cysts. Sagittal magnetic resonance imaging (MRI) reconstruction in patient with large echinococcal cyst; note daughter cysts in interior.
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Computed tomography (CT) appearance of biliary cystadenoma.
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Resection of involved liver in polycystic liver disease.
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Laparoscopic view of initial hepatic cyst puncture, before unroofing. Lesion is located high in right liver near the diaphragm.
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Laparoscopic view of beginning of unroofing of large simple hepatic cyst near dome of right liver.
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Drawing of final result of laparoscopic unroofing of a large simple hepatic cyst in right liver.
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Initial penetration of hepatic cyst with drainage of cyst fluid.
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Unroofing of hepatic cyst.
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Omentum sutured to excised margin.
Tables
First Author (Year) |
Institution |
Number of Patients |
Success Rate, Simple Cysts |
Success Rate, Polycystic Liver Disease |
Morino (1994) [7] |
University of Torino, Italy |
17 |
100% |
40% |
Krahenbuhl (1996) |
University of Bern, Switzerland |
8 |
100% |
N/A |
Hansen (1997) [8] |
University of California, San Francisco, United States |
19 |
94% |
0% |
Emmerman (1997) |
Eppendorf University, Hamburg, Germany |
18 |
89% |
N/A |
Fabiani (1997) [9] |
University of Nice, France |
10 |
100% |
N/A |
Martin (1998) [10] |
Royal Infirmary, Edinburgh, Scotland |
38 |
92% |
39% |
Katkhouda (1999) [11] |
University of Southern California, United States |
25 |
100% |
89% |
Zacherl (2000) [12] |
University Clinic of Surgery, Vienna, Austria |
11 |
86% |
N/A |
Fiamingo (2003) [13] |
University Hospital, Via Giustiniani, Italy |
15 |
89% |
50% |
Robinson (2004) [14] |
University of Colorado, United States |
11 |
N/A |
45% |
Konstadoulakis (2005) [15] |
Athens University, Greece |
9 |
N/A |
78% |
Fabiani (2005) [16] |
University Nice, France |
38 |
96%* |
N/A |
*Clinicoradiologic recurrence |
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