Hepatic Cyst/Abscess

Abstract

Hepatic cysts are common, occurring in at least 2–7% of the population, and are typically discovered incidentally with the frequent use of ultrasonography and computed tomography. Only about 16% of such cysts are symptomatic [1]. They may be either congenital or acquired. The more common congenital variety may represent malformed bile ducts while the acquired type of hepatic cyst usually arises as sequelae of inflammation, trauma or parasitic disease, and sometimes neoplastic disease [2].

Introduction

Hepatic cysts are common, occurring in at least 2–7% of the population, and are typically discovered incidentally with the frequent use of ultrasonography and computed tomography. Only about 16% of such cysts are symptomatic [1]. They may be either congenital or acquired. The more common congenital variety may represent malformed bile ducts while the acquired type of hepatic cyst usually arises as sequelae of inflammation, trauma or parasitic disease, and sometimes neoplastic disease [2].

Classification of cystic liver lesions according to etiology

Congenital

• Ductal (dilatation of intrahepatic duct)   – Ductal cyst   – Caroli’s disease(cystic dilatation of intrahepatic bile ducts)

• Parenchymal (solitary or polycystic)

Acquired

• Infectious   – Bacterial—Pyogenic liver abscess   – Parasitic—Hydatid cyst, amoebic liver abscess

• Traumatic  • Neoplastic (biliary cystadenoma, cystadenocarcinoma)

There has been a significant improvement in diagnosis, treatment, and outcome of these hepatic lesions.

Congenital Cyst

• Presentation: They are usually asymptomatic. They can cause right upper quadrant pain due to stretching of Glisson’s capsule and bloating if large due to pressure effect. If very large, they may be palpable abdominally. Acute abdominal pain may occur due to hemorrhage in cyst or its rupture. Sometimes they may cause jaundice due to compression effect.

• Investigations: Ultrasound, CT scanning, and MRI can show cyst anatomy. LFT may be slightly abnormal.

• Treatment: Options include watchful monitoring if asymptomatic and aspiration/sclerotherapy if symptomatic.Laparoscopic/open fenestration may be effective in certain cases. Liver transplantation is occasionally needed in case of polycystic liver disease or Caroli’s disease with liver failure [3].

Neoplastic Cysts

• Presentation: usually asymptomatic or vague symptoms including bloating, nausea, and fullness can occur. Abdominal pain and biliary obstruction can result as they enlarge.

• Investigation: LFT may be normal. Carbohydrate antigen (CA)—19–9 may be raised. Typical pattern may be seen on CT-scan.

• Treatment: The definitive treatment is complete surgical resection.

Liver Abscess

• Liver abscesses are caused by bacterial (pyogenic abscess), parasitic (amoebic abscess), or fungal organisms. In developed countries pyogenic abscesses are the most common but worldwide, amoebic abscesses are the most common [4].

• Pyogenic liver abscesses(PLA) are usually multiple but may be single too, affecting right lobe of liver in 74% cases [5]. Most are secondary to infection originating in the abdomen. It may be iatrogenic secondary to liver biopsy or a blocked biliary stent. Bacterial endocarditis and dental infection are other causes. It is more common in immunocompromised. It can be a complication of umbilical vein catheterization in infants. It tends to be polymicrobial. Organisms are usually of bowel origin. Klebsiella pneumoniae has emerged as the most common organism [6]. Other organisms include E. coli, Bacteroid species, enterococci, streptococci, and staphylococci.

• Amoebic liver abscesses (ALA), caused by Entamoeba histolyticais usually single, common in tropical and subtropical areas and more likely if there is poor sanitation and overcrowding. Transmission is via feco-oral route. Amoebae invade intestinal mucosa and gain access to portal venous system. It affects right lobe in 80% cases [7].

• Presentation: Multiple abscesses tend to present more acutely while single ones are more indolent. Patients usually present with right upper quadrant pain which may refer to the right shoulder, associated with swinging fever, night sweats, nausea, vomiting, anorexia, and weight loss. Patients may have cough and dyspnea due to diaphragmatic irritation. Jaundice may be present in 6–29% of cases [8]. Examination may reveal tender hepatomegaly.

• Investigation: Total leucocyte count and ESR will be raised. Mild normochromic normocytic anemia may be present. LFT may be deranged (raised transaminase, raised alkaline phosphatase, raised bilirubin, low albumin). Blood culture will be positive in 50% of cases of PLA [9]. Stool may contain cysts or trophozoites of E. histolytica in ALA. Serology will be helpful in ALA. Chest x-ray may reveal raised right hemidiaphragm, atelectasis, or pleural effusion. Ultrasonography can show abscess (usually single central location in ALA, multiple peripheral location in PLA). CT scan is good for detecting small abscesses as well as for detecting the intra-abdominal cause.

• Treatment: Most of the cases of liver abscesses are managed by either antibiotics alone or combination of antibiotics and drainage guided by ultrasonography or CT. Percutaneous Catheter Drainage (PCD) is more effective than Percutaneous Needle Aspiration (PNA) because it facilitates a higher success rate, reduces the time required to achieve clinical relief, and supports a 50% reduction in abscess cavity size [10]. The combination of third-generation cephalosporin and metronidazole is the first-line choice of antibiotics in PLA. Treatment may be needed for upto 12 weeks and should be guided by the clinical picture, culture, and radiological evidence. Metronidazole is the treatment of choice in ALA. Use of percutaneous drainage has steadily increased whereas the use of surgical drainage has declined [11]. Surgery is needed if the abscess has ruptured or if there is known pathology such as appendicitis.

Hydatid Cysts

• Aetiopathogenesis: It is caused by infection with metacystode (larval stage) of Echinococcus tapeworms (E. granulosus and E. multilocularis). Canine, carnivores such as dogs, and wolves act as definitive hosts where adult form of parasites live and sexual cycle occurs. They give eggs which are passed into feces of these hosts. These eggs are ingested by herbivores such as sheep, an intermediate host. These eggs are turned into larval stage (child form). Herbivores are intermediate hosts because they are eaten by the definitive hosts. This is how cycle of parasitic zoonoses completes. Human are not supposed to come in between these two hosts. But if accidentally, human ingest these eggs by ingestion of food/water contaminated with eggs or through close contact with infected dogs, human acts as intermediate host and is a dead end because they are not further eaten up by carnivores. In humans the eggs reach small intestine, invade the intestinal wall with three pairs of hooks and reach portal vein. Since right portal branch is small in length and course is relatively straight, and mostly going to the right upper segments of liver. That is why most common site of hydatid cyst in liver is segment 7/8. Larvae that escape hepatic filtering are carried to the lung. From the lung, larvae may disseminate to other distant body parts such as brain, bone, spleen, and kidney.

• Initially, when eggs attach to capillary in liver, they proliferate and are active. But as immunity starts fighting with these eggs, they may become dead. Hence, the fate of eggs is determined by immunity [12]. Larvae that escape the host’s defense, develop into small cysts surrounded by a fibrous capsule. These cysts grow at a rate of 1–3 cm/year and may remain undetected for years [13]. Thus, they can reach very large sizes before they become clinically evident. A cyst in liver is composed of three layers:

  • Adventia (pericyst): consists of compressed liver parenchyma and fibrous tissue induced by expanding parasitic cyst.

  • Laminated membrane (ectocyst): is elastic white covering, easily separable from the adventitia.

  • Germinal epithelium (endocyst): is a single layer of cells lining the inner aspect of the cyst and is the only living component, being responsible for the formation of other layers as well as hydatid fluid and brood capsules within the cyst. In some cysts, laminated membrane may eventually disintegrate and brood capsules are freed and grow into daughter cysts.

• Presentation: There is usually no symptom in acute stage when eggs just infect the liver. When a cyst is formed, this will produce pressure symptoms most commonly as the right upper abdominal heaviness or pain [14]. Hepatomegaly may be present. If cyst becomes so large, it may produce portal hypertension and obstructive jaundice. Sometimes acute abdominal pain may occur and this is because of complications (such as perforation, infection), not just because of cyst formation. Very rarely anaphylaxis can also occur following perforation.

• Investigation: There will be eosinophilia, slightly deranged LFT. Serological test is of use for diagnosis.ELISA (Enzyme-linked Immunosorbent assay) has sensitivity above 90% and is useful in mass-scale screening. The counter-immunoelectrophoresis has the highest specificity (100%) and high sensitivity (80–90%). CASONI test has been used most frequently in the past but is at present considered only of historical importance because of low sensitivity. The sensitivity and specificity of ELISA are highly dependent on the method of antigen preparation, and cross-reactions with other helminthic diseases occur if crude antigen is used. Purified fraction may yield high sensitivity and specificity [15]. Ultrasound is the imaging modality of choice for diagnosis. CT and MRI are modalities of choice for number, site, and identification of complications. CT is better than MRI to look for calcification while MRI is better to look for biliary involvement. Indirect signs of biliary communication are deformed cyst, Crampledhydatid membrane, dilatation of biliary tree, close contact between cyst and biliary branch, interrupted calcified wall, and fluid-fat level in the cyst. WHO has developed a standardized classification system [16], originally developed by Gharbi and colleagues in 1981, and is currently the screening method of choice (Table 1).

• Treatment: All of the four modalities (chemotherapy, interventional radiology, endoscopic procedure, and surgery) have a role in its management. The choice of an optimal treatment should be carefully assessed in each case [17].

• Chemotherapy (albendazole 400 mg twice a day): It is useful in type 1 and 3a WHO cysts, where the cyst is single, less than 5 cm. The rationale is that the drug can penetrate the cyst wall. But when the cyst has predominant solid component or daughter cysts, the drug may not penetrate even after long-term use of chemotherapy and drugs should not be used. However, it can be used as adjuvant or neoadjuvant to PAIR or surgery to prevent recurrence. Four days to 1 month of preoperative therapy and 4–6 months postoperative therapy with albendazole are recommended. As per WHO, 3 months preoperative therapy is most effective. It is of no use in calcified dead cyst.

• Interventional radiology:

  Treatment options are

  • PAIR (Percutaneous Aspiration Injection Reaspiration):

Table 1 Classification of hydatid cyst of liver

Indications are [18]:

• CE1, CE2, CE3.

• Multiple cysts if accessible to puncture.

• Infected cyst.

• Patients who fail to respond to medical management.

• Patients in whom surgery is contraindicated.

• Patients who relapse after surgery.

Contraindications

• noncooperative patient,

• inaccessible to puncture,

• cyst communicating with biliary tree,

• inactive/calcified cyst.

  • PAIR-D (D=Drainage) is a variant of PAIR associated with insertion of intracystic catheter at the end of the procedure and drained for 24 h.

  • D-PAI (Double Puncture Aspiration Injection): It is used for univesicular cyst. With ultrasound guidance, fine needle drainage of cyst was performed, 95% alcohol was injected, and left in situ partly filling the cyst cavity. The same procedure is performed 3 days later [19].

  • PEVAC (Percutaneous Evacuation of cyst contents): It is used for multivesicular cysts. It involves the following steps: ultrasound-guided cyst puncture and aspiration of cyst fluid to release intracystic pressure and thereby avoid leakage; insertion of a large bore catheter; aspiration and evacuation of daughter and endocyst by injection and reaspiration of isotonic saline; cystography; injection of scolicidal only if no cystobiliary fistula is present; external drainage of cystobiliary fistula combined with sphincterotomy; and catheter removal after complete cyst collapse and closure of cystobiliary fistula [20].

Complications of Interventional radiology procedures are

• Same risk as of any puncture such as hemorrhage and infection.

• Secondary echinococcosis caused by spillage.

• Anaphylactic shock or allergic reaction.

• Chemical cholangitis if cyst communicates with biliary tree.

• Systemic toxicity of scolicidal agent if cyst is large.

Advantages of Interventional radiology procedures are

• Minimal invasiveness.

• Require less expertise.

• Reduced risk compared to surgery.

• Reduced hospital time.

• Cost effective.

• Can be performed in remote areas with less infrastructures

• Surgery.

Preoperative evaluation includes

• Complete blood count and blood grouping.

• Electrocardiogram.

• Electrolytes.

• PT/INR.

• Renal and Liver function test.

• Review of imaging—triphasic CT or MRI

Indications of surgery are

• Complicated cysts.

• Large CE2-CE3b cysts.

• Single liver cyst located superficial and carries risk of perforation (such as following trauma).

• Cyst communicating biliary tree.

• Infected cyst.

• Cyst exerting pressure effects on adjacent vital organ

Contraindication for surgery are

• General contraindication such as multiple medical comorbidities.

• Multiple cysts in multiple organs.

• Cysts that are difficult to access.

• Dead calcified cyst.

• Very small cyst

Aims of surgery are

• Complete extirpation of the parasites.

• Obliteration of residual cavity.

• Identification and management of biliary fistula and other complications

Surgical procedures can be conservative procedures (partial cystectomy or deroofing, marsupialization, and external drainage) or radical procedures (pericystectomy, subadvential cystectomy, and formal liver resection). These procedures can be performed laparoscopically or via open surgery. There are a few contraindications of laparoscopic procedure and these are

• Severe cardiopulmonary disease is unlikely to tolerate prolonged CO₂-induced pneumoperitoneum and deemed unfit for laparoscopy by the anesthesiologists.

• Previous multiple upper abdominal surgery likely to have adhesions and thus limiting vision and increasing the difficulty level of laparoscopic dissection.

• Recurrent hydatid cysts.

• Deep located cysts.

• Rupture of cyst in biliary tree.

Conservative procedures are safe and technically simple. However, their disadvantages are high postoperative complications and recurrence rate as shown in Table 2. Radical procedures have a lower rate of recurrence [21] but many authors still consider them inappropriate, claiming that intraoperative risks are too high for benign disease [22].

Table. 2 Complications of conservative surgery

Endoscopic management: ERCP will be helpful for major biliary communication with dilated bile duct [23].

Operative Details of Various Surgical Procedures

Laparoscopic Deroofing, a conservative procedure Iis most common surgery being performed for hydatid cyst.

Recommended instruments

• One 10 mm trocar.

• A 30° angled laparoscope.

• Two 5 mm trocar.

• One 10 mm trocar.

• One 5 mm grasping forceps.

• One generated grasping forceps.

• A 5 mm hook.

• Irrigation and aspiration probe.

• Energy devise: (Harmonic scalpel, ligasure, etc.).

• Specimen retrieval bag.

• Liver detractors (may be required to retract liver)

Figure1 describes operation theater setup and position of surgeon and the assistants. The surgeon usually stands on the left-hand side of the patient but may stand between the legs of the patient placed in a “Y” position.

Fig. 1

Operation theater setup and position of surgeon and the assistants

Technique

• All patients are operated under General anesthesia with a Foley’s catheter and nasogastric tube placed immediately after induction in either supine position or the French position

• A 10 mm port at the umbilicus houses the 30° telescope. A 5 mm trocar is placed just below the xiphoid process to the right or the left of the falciform ligament, depending on the location of the cyst. This port is used to expose the liver. One 5 mm and one 10 mm ports, in the right and left flank, allow the surgeon to puncture the cyst dome, aspirated its contents, and excise the cyst wall in a careful sequential fashion to facilitate homeostasis (Fig. 2.

• A gauge soaked with 3% saline or 10% betadine is kept around the cyst to prevent contamination by spillage before puncture of the cyst (Fig. 3).

• Decompression of the cyst by aspiration of the cyst fluid using a wide bore needle through one of the 5-mm ports or by direct percutaneous entry under laparoscopic guidance taking care to avoid spillage and by the use of at least one continuous suction cannula around the needle puncture site.

• Once cyst is punctured, cyst content should be examined as further step depends on it. In a typical viable cyst, the content will be clear with sand and debris of broad capsules. The content will be initially clear and later turns bilious in case of cyst with biliary communication due to valvular mechanism. (Biliary system pressure is 15–20 cm of H2O while intracystic pressure is 30–80 cm of H2O) Infected cyst has purulent content with flakes. Dead cyst has toothpaste-like content.

• Aspiration of as much of the cyst fluid and injection of equal amounts of scolicidal agents (10% povidone iodine or hypertonic saline) into the cyst cavity without removing the needle. Hypersonic saline is preferred because stain of providing iodine may mimick bile leak. In case of biliary communication, avoid injection of scolicidal agent 10% betadine because of fear of chemical cholangitis.

• Aspiration of the cyst contents after 10 min using high-powered suction at a negative pressure via 10 mm trocar introduced directly into the cyst under vision (Fig. 4).

• Scoring of Glisson‘s capsule of area to be deroofed with high-frequency electrosurgery.

• Mesenchymal dissection can be performed using ultrasonic dissector.

• Once the dome of cyst is deroofed, all residual elements should be evacuated until the cavity is clear.

• Direct inspection of the interior of the cyst by introducing the scope into the cyst to look for remaining cyst elements and biliary leakage, if any, for subsequent attention.

• Removal of the cyst wall and cyst elements by using an impermeable specimen bag.

• The specimen is extracted either by partial morcellation, dilatation at the umbilicus, enlarging another port site or by a small MC Burney or subcostal incision.

• Cholangiography or ICG (Fig. 5) is useful to detect bile leak.

• Inspection of raw surface of liver, and if required it is covered with fibrin glue.

• Management of Residual cavity: Various options are

  • Water-tight suturing without drain.

  • Marsupialization.

  • Capsulorrhaphy and Capitonnage.

  • Omentoplasty: It is the option of choice nowadays. A viable flap of omentum is sutured to cyst cavity and drain is kept.

• Sending scolices for confirmation by microscopy or for culture, if deemed infected.

Fig. 2

Port placement

Fig. 3

Cystic lesion isolated from rest of abdominal cavity with Betadine-soaked gauge

Fig. 4

Aspiration of cyst content with 10 mm suction

Fig. 5

Indocyanine Green (ICG) imaging showing no biliary communication of cyst

Other Operative Procedures

Radical procedures include pericystectomy, subadvential cystectomy, and formal liver resection (Fig. 6). Radical surgery has pros and cons shown in Table 3.

Fig. 6

(a) various layers of hydatid cyst (b) total cystectomy (c) subtotal cystectomy (d) hepatectomy

Table 3 Pros and cons of radicle procedure

Indications of radical procedure are:

• Large cystobiliary communication—unable to manage by Roux-en-Y anastomosis.

• Hydatid cyst with biliary obstruction leading to atrophy of segment.

Complications of Hydatid cysts of liver: The most common complications in order of frequency are infection, biliary communication, rupture into peritoneal cavity/pleural cavity, and portal hypertension [24].

Biliary Communication and its Management

The incidence of cysto-biliary communication ranges between 3 and17% [25]. The rupture of hydatid cysts into biliary ducts and the migration of the hydatid material in the biliary tree lead to other biliary complications such as cholangitis, sclerosis odditis, and hydatid biliary lithiasis. The diagnosis of this complication can usually be made by using ultrasound and abdominal CT scan. The presence of dilated common bile duct, jaundice, close proximity of cystic lesion to major ducts are strongly suggestive of cystobiliary communication. The various treatment options are as follows:

• Direct suturing of fistula orifice with the absorbable suture is indicated if perifistulous cyst wall is not calcified or too fibrotic. If calcified, suturing with omentoplasty may be helpful.

• In case of hydatid cyst in main biliary tree, CBD exploration with removal of cyst material with T-tube drainage is indicated if ERCP is not available.

• Cyst communication with a large duct may require drainage with Roux-en-Y hepaticojejunostomy.

• Radical surgery is the best procedure for large biliary-cyst fistula.