You are in: eMedicine Specialties > General Surgery > Abdomen Hepatic CystsArticle Last Updated: Feb 21, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Heidi Holman Jackson, MD, Staff Physician, Department of Surgery, University of Utah School of Medicine Heidi Holman Jackson is a member of the following medical societies: American College of Surgeons, American Medical Women's Association, and Southwestern Surgical Congress Coauthor(s): Sean J Mulvihill, MD, Chief, Professor, Department of Surgery, University of Utah School of Medicine Editors: Brian James Daley, MD, MBA, FACS, Associate Program Director, Professor, Department of Surgery, Division of Trauma and Critical Care, University of Tennessee School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; BS Anand, MD, Department of Internal Medicine, Division of Gastroenterology, Professor, Baylor University College of Medicine; Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital Author and Editor Disclosure Synonyms and related keywords: simple cysts, solitary nonparasitic cysts of the liver, congenital polycystic liver disease, parasitic cysts, hydatid cysts, echinococcal cysts, cystic tumors, abscesses, Echinococcus granulosus, cystic hepatic lesions, cystadenoma, cystadenocarcinoma, autosomal dominant polycystic kidney disease, jaundice, cholangitis, anaphylactic shock INTRODUCTIONSection 2 of 12
  The term hepatic cyst usually refers to solitary nonparasitic cysts of the liver, also known as simple cysts. However, several other cystic lesions must be distinguished from true simple cysts. Cystic lesions of the liver include simple cysts, multiple cysts arising in the setting of polycystic liver disease, parasitic or hydatid (echinococcal) cysts, cystic tumors, and abscesses. These conditions can usually be distinguished on the basis of the patient's symptoms and the radiographic appearance of the lesion. Ductal cysts, choledochal cysts, and Caroli disease are differentiated from hepatic cysts by involvement of the bile ducts and are not reviewed in this article. History of the ProcedureSee Imaging Studies. ProblemFrequencyThe precise frequency of liver cysts is not known because most do not cause symptoms, but liver cysts have been estimated to occur in 5% of the population. No more than 10-15% of these patients have symptoms that bring the cyst to clinical attention. Hepatic cysts are usually found as an incidental finding on imaging or at the time of laparotomy. Most series in the literature are relatively small, reporting fewer than 50 patients each. EtiologySimple cysts The cause of simple liver cysts is not known, but they are believed to be congenital in origin. The cysts are lined by biliary-type epithelium (see Media file 1) and perhaps result from progressive dilatation of biliary microhamartomas. Because these cysts seldom contain bile, the current hypothesis is that the microhamartomas fail to develop normal connections with the biliary tree. Typically, the fluid within the cyst has an electrolyte composition that mimics plasma. Bile, amylase, and white blood cells are absent. The cyst fluid is continually secreted by the epithelial lining of the cyst. For this reason, needle aspiration of simple cysts is not curative. Polycystic liver disease Adult polycystic liver disease (AD-PCLD) is congenital and is usually associated with autosomal dominant polycystic kidney disease (AD-PKD). Mutations in these patients have been identified in PKD1 and PKD2 genes. Occasionally, PCLD has been reported in the absence of polycystic kidney disease. In these patients a third gene, protein kinase C substrate 80K-H (PRKCSH), has been identified. Despite these differences in genotype, patients with PCLD are similar phenotypically. In patients with polycystic kidney disease, the kidney cysts usually precede the liver cysts. PKD often results in renal failure, whereas liver cysts only rarely are associated with hepatic fibrosis and liver failure. Neoplastic cysts Liver tumors with central necrosis visualized on imaging studies are often misdiagnosed as liver cysts. True intrahepatic neoplastic cysts are rare. The cause of cystadenomas and cystadenocarcinomas is unknown, but they may represent proliferation of abnormal embryonic analogs of the gallbladder or biliary epithelium. These cystic tumors are lined with biliary-type cuboidal or columnar cells and are surrounded by ovarianlike stroma. Cystadenoma is a premalignant lesion with neoplastic transformation to cystadenocarcinoma confirmed by tubulopapillary architecture and invasion of the basement membrane. Hydatid cysts Hydatid cysts are caused by infestation with the parasite Echinococcus granulosus. This parasite is found worldwide, but it is particularly common in areas of sheep and cattle farming. The adult tapeworm lives in the digestive tract of carnivores, such as dogs or wolves. Eggs are released into the stool and are inadvertently ingested by the intermediate hosts, such as sheep, cattle, or humans. The egg larvae invade the bowel wall and mesenteric vessels of the intermediate host, allowing circulation to the liver. In the liver, the larvae grow and become encysted. The hydatid cyst develops an outer layer of inflammatory tissue and an inner germinal membrane that produces daughter cysts. When carnivores ingest the liver of the intermediate host, the scolices of the daughter cysts are released in the small intestines and grow into adult worms, thus completing the life cycle of the worm. Hepatic abscesses Hepatic abscesses can be amebic or bacterial in origin. Entamoeba histolytica is the causative agent in amebic abscesses. It is contracted by ingestion of food or water contaminated by the cyst stage of the parasite. Amebiasis generally only involves the intestine but can invade the mesenteric venules resulting in liver abscesses. Its only host is the human. Pyogenic abscesses can be a result of instrumentation but are most often caused by ascending cholangitis. Microorganisms isolated are most often bowel flora. Other routes of contamination include the portal vein and hepatic artery. Patients with intra-abdominal infections may present with liver abscesses with extension of bacteria through the portal venous system. Hematogenous spread via the hepatic artery in patients with septicemia is rare. PathophysiologySee Etiology. ClinicalSimple cysts Simple cysts generally cause no symptoms but may produce dull right upper quadrant pain if large in size. Patients with symptomatic simple liver cysts may also report abdominal bloating and early satiety. Occasionally, a cyst is large enough to produce a palpable abdominal mass. Jaundice caused by bile duct obstruction is rare, as is cyst rupture and acute torsion of a mobile cyst. Patients with cyst torsion may present with an acute abdomen. When simple cysts rupture, patients may develop secondary infection, leading to a presentation similar to a hepatic abscess with abdominal pain, fever, and leukocytosis. Polycystic liver disease PCLD rarely arises in childhood. These cysts are observed at the time of puberty and increase in adulthood. They occur as part of a congenital disorder associated with PKD. Women are more commonly affected, and an increase in cyst size and number is correlated with estrogen level. In PCLD, hepatomegaly may be prominent, and, occasionally, patients progress to hepatic fibrosis, portal hypertension, and liver failure. Complications, such as rupture, hemorrhage, and infection, are rare. However, patients do present with abdominal pain as the cysts enlarge. Neoplastic cysts Cystadenoma most often occurs in middle-aged women. However, cystadenocarcinoma equally affects both genders. Most patients are asymptomatic or have vague abdominal complaints of bloating, nausea, and fullness. These patients, like all those with hepatic cysts, eventually present with abdominal pain. Rarely, they present with evidence of biliary obstruction. Hydatid cysts Patients with hydatid cysts, similar to patients with simple cysts, are most often asymptomatic, but pain may develop as the cyst grows. Larger lesions typically cause pain and are more likely to develop complications than simple cysts. At the time of presentation, patients generally have a palpable mass in the right upper quadrant. Cyst rupture is the most serious complication of hydatid cysts. Cysts may rupture into the biliary tree, through the diaphragm into the chest, or freely into the peritoneal cavity. Rupture into the biliary tree may result in jaundice or cholangitis. Free rupture into the peritoneal cavity may cause anaphylactic shock. As with simple cysts, patients with hydatid cysts may develop secondary infection and subsequent hepatic abscesses. Hepatic abscesses Patients with hepatic abscesses present with abdominal pain, fever, and leukocytosis. Clinical history is important because of associated illnesses. Those patients with amebiasis can have history of diarrhea and weight loss, although some may be asymptomatic. Pyogenic abscesses often present with cholangitis, abdominal infections, or sepsis. Rarely, abscesses will rupture, and patients present with peritonitis. INDICATIONSSection 3 of 12
Treatment of PCLD or solitary nonparasitic cysts of the liver is indicated only in symptomatic patients. Asymptomatic patients do not require therapy because the risk of developing complications related to the lesion is lower than the risk associated with treatment. Patients with hydatid cysts should be treated to prevent complications related to cyst growth and rupture. If cysts on imaging studies show abnormalities suggestive of cystic tumors, resection is indicated. Abscesses should be treated at the time of identification, but percutaneous drainage and antibiotics are usually adequate treatment. RELEVANT ANATOMYSection 4 of 12
See Etiology and Pathophysiology. CONTRAINDICATIONSSection 5 of 12
Contraindications to treatment of symptomatic liver cysts relate mainly to underlying comorbid illnesses that increase surgical risk. In particular, congestive heart failure and liver failure with portal hypertension and ascites increase operative risk. Symptoms suggestive of angina or transient ischemic attacks should lead to further preoperative diagnostic studies to identify significant coronary or carotid arterial stenoses. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
Histologic FindingsHistologic 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. TREATMENTSection 7 of 12
Medical therapySimple cysts No medical therapy has proven effective in reducing the size of simple hepatic cysts. Percutaneous aspiration under ultrasound or CT guidance is technically simple but has been abandoned because the recurrence rates are nearly 100%. Aspiration combined with sclerosis with alcohol or other agents has been successful in some patients but has high failure and recurrence rates. Successful sclerosis depends on complete decompression of the cyst and apposition of the cyst walls. This is not possible if the cyst wall is thickened or if the cyst is large. Percutaneous catheters should not be placed to drain simple cysts because the cavity becomes contaminated, leading to the development of hepatic abscess. Unlike the typical pyogenic hepatic abscess, this problem is difficult to resolve with repeated catheter placements because of continued secretion from the cyst epithelium. Polycystic liver disease/neoplastic cysts No options are available for the medical treatment of PCLD or cystadenocarcinoma. Because of the malignant potential of cystadenoma, a role also does not exist for medical therapy for this lesion. Hydatid cysts Medical therapy with antihydatid agents, albendazole and mebendazole, is relatively ineffective. These drugs are used as adjuvant treatment, but they do not replace surgical or percutaneous therapy. In surgically treated patients, the use of antihydatid agents is generally given perioperatively; continuation is limited to those who have spillage of cyst fluid at the time of operation or to those with cyst rupture. Antihydatid agents are used in conjunction with percutaneous treatment. Medical therapy should be started 4 days prior to percutaneous treatment and continued either for 1 month (albendazole) or for 3 months (mebendazole), according to the World Health Organization recommendations. PAIR (puncture, aspiration, injection, reaspiration) is a percutaneous treatment technique for hydatid disease. In this minimally invasive method, a needle is introduced into the cyst under ultrasound guidance. Cyst fluid is aspirated and analyzed. Hypertonic saline or ethanol is then injected and reaspirated. PAIRD (puncture, aspiration, injection, reaspiration, drainage) is similar to PAIR except that a catheter is left in place after completion of the procedure. PAIRD is most often used for large cysts. This percutaneous treatment with sclerosing agents was introduced in the 1980s. Since that time, its use in the treatment of hydatid cysts has been somewhat controversial. However, as this technique has become more common and its safety and efficacy have been reported in the literature, it has been increasingly accepted as a treatment option for hydatid disease. The World Health Organization currently supports PAIR as an effective alternative to surgery, although its use is limited. The World Health Organization guidelines for indications and contraindications of PAIR are as follows:
Patients should be followed clinically after PAIR treatment. Recurrence is increased in more complicated cysts, including those with multiple daughter cysts. PAIR should only be performed in highly specialized centers with appropriately trained and experienced staff. In addition, an anesthesiologist should be present for monitoring and treatment in the event of anaphylactic shock. Surgeons should be notified immediately in case of complication. Hepatic abscesses Patients with liver abscesses are immediately started on antibiotics/amebicides. If abscesses are small, patients may respond to medications alone. More likely, these patients will require the addition of percutaneous drainage for eradication. Surgical therapySimple cysts Most patients with simple cysts are asymptomatic and require no treatment. When the cysts become large and cause symptoms, such as pain, treatment is warranted. Surgical treatment of simple liver cysts involves "unroofing" the cyst by excising the portion of the wall that extends to the surface of the liver. Excision of this portion of the cyst wall at the liver surface produces a saucer-type appearance in the remaining cyst so that any fluid secreted from the remaining epithelium leaks into the peritoneal cavity where it can be absorbed. Although ablating the remaining epithelium with electrocautery or an argon beam coagulator is possible, this generally is not required because the volume of fluid secreted each day can be absorbed by the peritoneum without any consequence. Historically, treatment of symptomatic hepatic cysts required laparotomy, but, today, cyst unroofing can be successfully performed laparoscopically. Anecdotal reports of laparoscopic treatment became common by the mid 1990s, and, currently, the laparoscopic approach is considered the standard of care. When compared to laparotomy, this technique is associated with less postoperative pain and disability, shorter duration of hospital stay, and superior cosmetic results. Polycystic liver disease In AD-PCLD, enlargement of the liver occurs slowly and only rarely compromises liver function. Only those patients with clearly disabling pain should be considered for surgery. In patients with PCLD, the surgical goal is to decompress as much of the cystic liver as possible. This can be accomplished by a combination of unroofing and fenestration or, in selected patients, by resection of the involved portion of the liver (see Media file 7). Recurrence of symptoms with either procedure is high as new cysts replace those that have been resected. Small numbers of patients have been treated with liver transplantation. Neoplastic cysts Several surgical methods for treatment of cystadenoma and cystadenocarcinoma have been described. Regardless of surgical technique, all surgical options should result in complete ablation of the tumor. Enucleation and formal resection have been accepted as appropriate treatment options. Fenestration and complete fulguration have also been implemented, although, in this method, complete ablation cannot be confirmed by pathology. Hydatid cysts All patients with hydatid disease should be considered for percutaneous or surgical treatment because of the risk of life-threatening complications of untreated disease. More complicated cysts are better managed surgically. Treatment of hydatid cysts is associated with 2 technical problems: risk of anaphylaxis from spillage of cyst fluid containing eggs and larvae into the peritoneal cavity and recurrence caused by residual eggs in incompletely removed germinal membranes. To prevent these problems, most surgeons use a technique in which the cyst contents are aspirated and replaced with a hypertonic saline solution to kill residual daughter cysts in the germinal membrane before unroofing and pericystectomy. The goal of the latter procedure is to excise the germinal membrane, leaving the inflammatory and fibrous components of the cyst wall in situ. Attempts to excise the entire cyst wall or to perform formal hepatectomy for hydatid cysts have largely been abandoned because of increased surgical morbidity. Hepatic abscesses In general, abscesses are adequately managed by antibiotics and percutaneous drainage. If abscesses persist despite attempted percutaneous drainage, surgical drainage is indicated. Other surgical indications include large cysts at risk of rupture and abscesses not anatomically amenable to percutaneous treatment. Technical points in surgical therapy
Preoperative detailsPrepare patients for general endotracheal anesthesia. Prophylactic antibiotics are not necessary. The patient is positioned supine, with placement of orogastric and bladder catheters to decompress the stomach and bladder. The abdomen is prepared and draped in a sterile fashion. Intraoperative detailsThe operation is begun by inducing pneumoperitoneum with carbon dioxide gas via placement of a Veress needle or Hasson trocar. Generally, 3 laparoscopic ports are required, one for the telescope with camera, one for retraction, and one to carry out the dissection. The extent of the cyst is usually readily apparent on laparoscopic inspection, but, if not, laparoscopic ultrasonography can be performed to define the cyst anatomy. The line of the intended unroofing is marked with electrocautery, and the cyst excision itself is undertaken with electrocautery or a harmonic scalpel (see Media files 8-10). Excision of the entire cyst wall is neither necessary nor desired and, if attempted, carries the risk of injury to portal or hepatic venous vessels that may be stretched over the cyst wall. In patients where the proportion of the cyst wall that can be excised easily is small, omentum should be positioned on a pedicle into the cyst cavity to prevent closure of the roof defect and cyst recurrence. The omentum should be sutured or clipped to the edges of the excision margin. After ensuring that hemostasis is complete, the pneumoperitoneum is desufflated and the trocar sites are closed. Waterproof dressings are applied. Postoperative detailsIn patients undergoing laparoscopic unroofing of simple hepatic cysts, the orogastric and bladder catheters can be removed before the patient awakens from anesthesia. A light diet is offered the evening of surgery, and most patients can be discharged home the following day. Generally, recovery is rapid, and most patients resume full activity within 1 week. Patients can shower with the waterproof dressings in place the day after surgery. The dressings can be removed after 2-3 days. Follow-upFollowing successful laparoscopic unroofing of a simple liver cyst, the patient is seen at a follow-up visit within 2 weeks and again 6 weeks after surgery to assess symptomatic relief and to identify complications, such as wound infection or ascites. Routine radiographic studies are not obtained unless symptoms recur. COMPLICATIONSSection 8 of 12
Complications of laparoscopic unroofing of simple liver cysts are uncommon. Trocar site infection is a rare occurrence. Unexpected leakage of bile from the cut edges of the cyst can lead to a subhepatic or subphrenic fluid collection or, rarely, bile ascites. In patients with polycystic liver disease, take care when performing unroofing and fenestration procedures to avoid injury to biliary or vascular structures in the compressed hepatic parenchyma between the cysts. In patients with hydatid cysts, take care to avoid spillage of cyst contents into the peritoneal cavity, which may cause anaphylaxis. OUTCOME AND PROGNOSISSection 9 of 12
Several small series of patients undergoing laparoscopic unroofing of simple hepatic cysts have reported cure rates of 90% or higher. Patients with PCLD have lower cure rates (see Table). Recent Series of Patients Undergoing Laparoscopic Unroofing of Liver Cysts
*Clinicoradiologic recurrence FUTURE AND CONTROVERSIESSection 10 of 12
In patients with simple liver cysts, the general agreement is that laparoscopic unroofing offers the best balance between efficacy and safety. How patients with PCLD should be treated remains less clear because the failure rates for laparoscopic unroofing and fenestration are high. Liver resection, though more effective, carries higher risks. The treatment of hydatid cysts continues to be controversial. As more experience is reported in the literature, indications for PAIR versus surgery are delineated. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
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