Ultrasound

Simple cysts are characterized by acoustic enhancement posterior to the mass. They are solitary, thin-walled without focal thickening or nodularity, and anechoic without debris, and they lack septa. Septa typically are found in cystadenomas (Fig. 7-1); mural or septal nodularity most typically is seen in cystadenocarcinoma (Fig. 7-2). Hydatid cysts are typically hypoechoic and contain concentric peripheral daughter cysts within the larger cyst, and may have partial or complete calcification of the cyst wall (Fig. 7-3). Additionally, biliary ductal dilation or intraductal debris may be found within the biliary tree. Layering of blood within cysts may be seen after hemorrhage.

Figure 7-1 Hepatic ultrasound of cystadenoma. Note various septa across cystadenoma of the left lobe of the liver.

Figure 7-2 Hepatic ultrasound of cystadenocarcinoma. Note thick, irregular mural nodularity along the periphery and septa of cystadenocarcinoma of the left lobe of liver.

Figure 7-3 Hepatic ultrasound (A) and CT (B) of a hydatid cyst (echinococcal) of the right lobe of the liver. Note multiple daughter cysts along the periphery of the primary cyst cavity.

Computed Tomography

Computed tomographic (CT) features of hepatic cysts are similar to features seen on ultrasound (see Fig 7-3). Cyst hemorrhage and infection are confirmed by intracystic fluid layering or increased density. Vascular enhancement within the cyst wall or mural nodules suggest a cyst-associated malignancy or a cystadenocarcinoma (Fig. 7-4), whereas only septations occur with cystadenoma (Fig. 7-5). Polycystic liver disease (PLD) usually has some component of hepatic venous compression, but ascites usually indicates marked compression of all the major hepatic veins and the retrohepatic inferior vena cava. CT can define the extent of the compression of the major hepatic veins and inferior vena cava and help determine the extent of cyst resection or fenestration required to resolve hepatic venous outflow obstruction.

Figure 7-4 A, Abdominal CT of a cystadenocarcinoma of the left lobe of the liver. Note the mural irregularities and papillary projections into the primary cyst. B, An additional CT scan of the same cystadenocarcinoma further depicts irregular papillary tumor nodules and mass formation within the cyst.

Figure 7-5 A, Abnormal CT of a cystadenoma of the left lobe. Note the spoke-wheel septations within the cyst. B, Intraoperative photograph of a cystadenoma of the left lobe of the liver. Note the lobulations on the surface of the cystadenoma.

Magnetic resonance imaging (MRI) should be reserved to address specific issues. If CT fails to define hepatic vasculature accurately, MRI can define the vascular anatomy without contrast media, which may be important in patients with PLD and renal failure.

Endoscopic retrograde cholangiopancreatography (ERCP) documents the site and degree of biliary obstruction or often the site of biliary communication in jaundiced patients. Finally, cholangiography is essential to differentiate bile duct cysts from hepatic cysts with biliary communication. Magnetic resonance cholangiopancreatography (MRCP) also can be used for definition of the biliary system.

Laparoscopic Cyst Excision

Generally, laparoscopic management should be considered before open laparotomy. Laparoscopic management is indicated in patients with symptomatic superficial cysts located within the anterior liver segments (III, IV, V, and VI) and in patients who have not had extensive upper abdominal surgery. Cysts in segments VII and VIII of the liver can pose technical problems if approached laparoscopically. The major problem is the abutment of the rim of the cysts to the diaphragm; when the liver returns to its normal position, the apposition of cyst rim to diaphragm prevents intraperitoneal drainage of cyst fluid with subsequent cyst recurrence.

The basic laparoscopic approach has been standardized. The cyst is punctured and the cyst contents aspirated. The cyst wall is grasped and excised widely to its interface with the hepatic parenchyma.

Endovascular staplers can be used for secure closure of larger vasculobiliary structures recognized intraoperatively at the cyst-parenchyma interface. Any thickened bands along the cyst periphery are controlled. After excision of the superficial cyst wall, the concavity of the residual cyst should be inspected. If irregularities are seen, biopsy is indicated. Ablation of the cyst lining by argon beam coagulation or topical sclerosant or omentoplasty may reduce the risk of recurrence.

Management by Laparotomy

I do not advocate laparoscopy for very large cysts in segments VII and VIII. Cysts complicated by active hemorrhage or enteric communication are probably also best treated by open laparotomy.

Wide excision is essential, preferably excising greater than half the cyst to prevent sealing of the cyst remnant by adjacent viscera or diaphragm or residual cyst wall contraction with cyst recurrence. If less than half of the cyst is excisable, omentoplasty and ablation of the residual cyst epithelium by coagulation or sclerosant should be performed. Alternatively, hepatic resection prevents recurrence totally.

I recommend ablation of the residual cyst wall with the argon beam coagulator followed by omentoplasty.