Laparoscopic Excision of Congenital Hepatic Cysts in the Pediatric Population: A Case Series and Literature Review

Case #1

A 7-week-old male infant presented with feeding intolerance and a palpable right upper quadrant abdominal mass. Ultrasound demonstrated a cystic lesion preoperatively believed to be a mesenteric cyst. Computed tomography (CT) scan was suggestive of a hepatic cyst measuring 4.7 × 5.7 cm. At laparoscopy, the hepatic cyst was mainly localized to the right lobe and was completely excised using the harmonic scalpel. Pathology revealed a benign lesion that was consistent with a congenital solitary nonparasitic hepatic cyst. At 1-year follow-up, there was no evidence of recurrence.

Case #2

A 6-year-old boy presented with abdominal pain and underwent evaluation for appendicitis. Ultrasound demonstrated a cystic mass associated with the liver. CT scan confirmed a multiloculated cystic lesion (4.5 cm × 5 cm × 5 cm) that was located near the falciform ligament. At laparoscopy, he was found to have a cyst in segment 4 of the left hepatic lobe. It was completely excised using the harmonic scalpel. An appendectomy was also performed for an appendicolith-identified intraoperatively. A superficial wound infection occurred postoperatively and was treated successfully with antibiotic therapy. Pathology revealed a benign solitary nonparasitic hepatic cyst. At 1-year follow-up, there was no evidence of recurrence.

Case #3

A 5-day-old boy was diagnosed prenatally with a suspected left congenital diaphragmatic hernia. At birth, he was found to have a thoracic cyst occupying most of the left chest and communicating anteriorly through a diaphragmatic defect, with a cystic lesion near the stomach. At thoracoscopy, it was confirmed that there was a solitary thoracic cyst with a stalk passing through the diaphragm. It was excised using the harmonic scalpel. A laparoscopy was then performed, revealing extension of the cystic lesion into the lesser sac and arising from the left hepatic lobe. It was completely excised using the harmonic scalpel. Laparoscopic repair of the diaphragmatic defect was also performed. Pathology revealed a benign solitary nonparasitic hepatic cyst. At 1-year follow-up, there was no evidence of recurrence.

Case #4

A 14-year-old male was found to have a 25 cm × 11 cm hepatic cyst. The cyst was adjacent to the left lateral segment of the liver. He underwent laparoscopic drainage of 3 L of cystic fluid and complete excision of the cyst. Pathology demonstrated a mesenchymal hamartoma with multiple biliary cysts. There were no noted postoperative complications. At 1-year follow-up, there was no evidence of recurrence.

Epidemiology

In 1856, Mickel described the first congenital solitary nonparasitic hepatic cyst in an adult. ¹¹ Between 1856 and 1995, more than 400 cases have been reported in the pediatric literature, but only 5% involve infants less than 2 years of age. ¹¹ True nonparasitic congenital hepatic cysts have a reported overall prevalence ranging between 0.1% and 2.5%,^2,12 although noninvasive imaging has shown that asymptomatic hepatic cysts are likely more common in the general population than originally believed. ³ Calculation of the precise frequency of congenital hepatic cysts in the pediatric population is difficult, because the lesions rarely produce symptoms and so they are usually not detected until adulthood when they may become symptomatic. Furthermore, only 10%–40% of congenital cysts are estimated to become symptomatic. ¹⁰ Quiescent lesions are usually discovered as an incidental radiographic, intraoperative, or autopsy finding. In a retrospective review at Boston Children's Hospital, Boston, MA, USA, in which 30 cases of congenital nonparasitic hepatic cysts were reviewed in children less than 8 years of age, only 40% of children were symptomatic from abdominal distension whereas 60% of lesions were incidental findings at autopsy. ²

When detected in adulthood, hepatic cysts are mainly found between 20 and 50 years of age with a median age at presentation of 48 years.^1,13 The female-to-male ratio is 5:1. ²

Classification and differential diagnosis

Hepatic cysts may be classified broadly into two major categories—congenital or acquired.^9,14 Each can usually be categorized on the basis of history, symptoms, and radiographic appearance.

Congenital hepatic cysts arise from abnormal development of the intra- or extrahepatic biliary tree. They are solitary (simple) or multiple (polycystic). ¹⁴ Unlike polycystic liver disease, simple hepatic cysts do not have a genetic basis, and there is no association with renal, splenic, pancreatic, or lung cysts. ²

Acquired hepatic cysts are parasitic (infectious) or nonparasitic (post-traumatic or neoplastic). ¹⁵ Parasitic cysts are usually hydatid cysts resulting from infection with the parasite Echinococcus granulosus. Most acquired nonparasitic hepatic cysts are post-traumatic pseudocysts. ¹⁵

Cystic neoplasms of the liver are rare. They include: primary biliary cystadenoma, cystadenocarcinoma, metastatic pancreatic or ovarian tumor, and solid hepatic tumor with cystic degeneration. ¹² Small asymptomatic hepatic cysts are considered benign, but they should be followed for growth and the possibility of malignant degeneration. ³ Cysts lined with squamous epithelium may be more prone to metaplasia and malignant transformation, ¹¹ but adenocarcinomas and sarcomas have also been described. ¹⁶ At operation, a thickened cyst wall and firm adherence to the surrounding liver are suggestive of malignancy. ¹² Septations, papillary structures, or multiloculated cysts should also raise the index of suspicion. ¹⁷ Evaluation of the cyst wall with an intra-operative frozen section can be useful if there is a concern for malignancy.

Since symptomatic hepatic cysts in infants and children can be quite large relative to the intraabdominal cavity, they can be difficult to distinguish from surrounding organs on radiographic imaging. Knowing the differential diagnosis is important to help decide appropriate management. In the newborn, the differential diagnosis of a cystic lesion in the right upper quadrant includes: choledochal cyst, hepatic cyst, enteric duplication cyst, congenital hepatic fibrosis, and mesenteric, ovarian, or renal cyst. ¹⁸ In the older child, the differential diagnosis also includes hydrops of the gallbladder, pancreatic cyst, mesenchymal hamartoma, hydronephrosis, Caroli's disease, tuberculous peritonitis, and necrotic metastases.^2,19 Simple congenital hepatic cysts have been reported in infants and children with other abnormalities, but they are not considered to be associated with a congenital syndrome.

Pathophysiology

Congenital hepatic cysts originate from the biliary tree and more specifically, they are believed to arise from enlargement of congenital aberrant biliary ducts. They are usually lined with biliary columnar epithelium, although squamous or cuboidal cells may be present. ¹⁵ Despite their biliary origin, only 25% of cysts have a connection with the biliary tree, ¹⁵ suggesting that the underlying etiology may be progressive dilatation of biliary microhamartomas secondary to failure of normal connections with the biliary tree. Differentiation between lesions that communicate with the biliary system and those that do not is essential for deciding appropriate management.

Although the exact etiology may be unclear, the overall pathogenesis involves a congenital malformation with accompanying inflammation and fluid accumulation from secreting biliary epithelium. ² Thus, destruction of the epithelium is the basis for treating these lesions.

The most common anatomic location is segment 5 of the right hepatic lobe, ¹⁹ with right lobe lesions reported in the literature twice as often as left. ² Unilocular cysts are much more common than multilocular cysts, with the multilocular type being extremely rare in children. ² Cysts can be solitary, multiple, or diffuse throughout the liver (polycystic disease). Regardless, they usually contain clear fluid with variable amounts of protein, cholesterol, blood cells, mucin, and epithelial cells. ¹⁹

Clinical presentation

The pathophysiology of simple hepatic cysts is predominantly related to the continuous secretion of fluid by epithelial cells. Despite this, only 10%–15% of hepatic cysts cause symptoms. ¹⁰ Most lesions are asymptomatic and discovered incidentally in adulthood. Abdominal discomfort and right upper quadrant pain are usually the first presenting symptoms in adults, but symptoms can remain quiescent because of the low internal pressure of the cysts. ¹⁹

In the pediatric population, a hepatic cyst may be first discovered on prenatal imaging. In children, progressive abdominal distension is the most common presenting sign.^1,2,7,11 Associated symptoms are related to the space-occupying effect of the lesion on adjacent viscera and include upper abdominal and right shoulder pain, nausea, emesis, gastroesophageal reflux, early satiety, dyspnea, and respiratory distress.^7,8 Pressure on the vertebral column may cause lumbar pain, and pressure on the bladder may cause urinary frequency. ¹⁰ Most cysts do not invade biliary or vascular structures, but they may cause obstruction or compression atrophy. ¹⁷ Occasionally, the cyst exerts pressure on the liver parenchyma or porta hepatis, ⁶ resulting in obstructive jaundice,^3,10,15 cholangitis, ¹² or portal hypertension. ¹⁰ Except for patients who present with obstructive jaundice, liver function tests are usually within normal range. ³ Liver failure has been reported, but it is extremely rare. ⁶ Urgent or emergent surgical resection is rarely necessary, and it is limited to acute complications, including infection, bile leak, rupture, peritonitis, torsion, and intra-cystic hemorrhage.^2,10,17

Treatment options

Treatment of congenital nonparasitic hepatic cysts is indicated for symptoms (abdominal pain, nausea/vomiting, obstruction), complications (perforation, secondary infection, internal bleeding, torsion), and to rule out malignancy. Nonsurgical and surgical options are available. Nonsurgical options include serial observation, and aspiration with or without sclerosis. Surgical options include enucleation (cystectomy), fenestration (unroofing), internal drainage, hepatic resection, and, rarely, hepatic transplantation. Celebi et al. performed a 10-year retrospective review of congenital hepatic cysts in their institution. ²⁰ Of the 67 pediatric cases diagnosed pre- or post-natally, 10 underwent open surgery with the main indication being a complication of the cyst or increasing size of the cyst, causing symptoms such as abdominal pain due to mass effect. Four patients underwent open fenestration, five underwent total enucleation, and one underwent a partial hepatectomy. Intraoperative cholangiogram was performed in cases where there was preoperative evidence of biliary communication. ²⁰

Nonsurgical therapy

Hepatic cysts were traditionally diagnosed when they were large enough to become apparent as an abdominal mass, or as an incidental finding during laparotomy or autopsy. Widespread use of improved imaging has led to increased detection of incidental lesions. ² Asymptomatic patients with small lesions do not necessarily require treatment, as the likelihood of complications is believed to be lower than the risk associated with treatment. ⁶ Although considered benign, untreated cysts must be followed with a serial ultrasound or CT scan because of the small risk of malignant transformation. ³

Treatment of a hepatic cyst requires ablation of the fluid-secreting epithelium. For this reason, simple percutaneous needle aspiration is almost universally ineffective and is associated with 100% recurrence.^6,10,13,18 As a result, simple aspiration has been abandoned as definitive therapy. It is only appropriate in select circumstances as a temporizing measure to relieve severe or life-threatening symptoms (e.g., respiratory distress in a newborn), or when definitive treatment is associated with high operative risk.

Several reports of sclerotherapy in the adult population have shown variable results, ¹⁰ though aspiration with sclerosis yields better results than aspiration alone. ¹⁴ Sclerotherapy is less invasive and is associated with fewer complications than surgical intervention, but it is associated with a higher recurrence rate.^6,18 In a study of 23 adults with symptomatic nonparasitic hepatic cysts, 100% (6/6) of those who underwent sclerotherapy had a recurrence of their cyst, whereas 25% (2/8) of the patients' status postlaparoscopic fenestration had a recurrence. ²¹ There are few reports of congenital hepatic cysts treated with sclerotherapy in the pediatric population. ²² Intracystic ethanol injection was used in at least one newborn infant with a rapidly enlarging hepatic cyst, with no evidence of recurrence at 7-year follow-up. ²³ Caution must always be used, as commonly used sclerosing agents (e.g., ethanol) can cause alcohol intoxication and irreversible sclerosing cholangitis. ¹⁴

Surgical therapy

Surgical intervention is reserved for significant abdominal or respiratory symptoms due to cyst growth, acute complications, or neoplastic growth. Surgical options include fenestration, enucleation, internal drainage, resection, and rarely, hepatic transplantation. The basic principles are to completely remove or destroy the cyst epithelium, and to provide a mechanism for drainage of the cyst fluid. If the cyst communicates with the biliary tree, an internal drainage procedure (cystgastrostomy or cystjejunostomy) is necessary. If the cyst does not communicate with the biliary system, free drainage into the peritoneal cavity is acceptable, because the fluid is reabsorbed by the peritoneum. Techniques for surgical therapy have largely been adopted from the adult population.

In 1968, Lin et al. described the technique of wide fenestration for polycystic liver disease in two pediatric and three adult patients. ²³ Since that time, the technique has also been applied successfully by many surgeons to treat simple hepatic cysts. ³ Wide fenestration consists of creating a large opening or window on the nonparenchymal side of the cyst to allow free drainage of fluid into the abdominal cavity. Although the cyst wall continues to secrete, the peritoneal lining reabsorbs the fluid. Symptomatic relief is achieved, because fluid is no longer accumulating within the enclosed space of the cyst wall. Since fenestration does not involve dissection of hepatic parenchyma, it is associated with lower morbidity than enucleation. Fenestration has a recurrence rate ranging from 0% to 38%. ¹⁰ Adding omentoplasty and oversewing the margins with a running suture appear to reduce the recurrence rate to 0%–14%. ¹⁰

Enucleation (complete cyst excision) involves complete removal of the cyst epithelial lining, often with a small rim of the liver, resulting in complete cure. Complete cyst excision is often considered the treatment of choice for congenital hepatic cysts found in adults. ¹⁸ Recurrence after partial resection is related to the remaining epithelium within the cyst wall. Even a small amount of residual epithelium can lead to recurrence. Although enucleation yields the lowest recurrence rate (4%), morbidity can be high, as the operation requires dissection of liver parenchyma with the associated risks of hemorrhage and bile leak. ²⁴

In 1991, Z'Graggen reported the first laparoscopic fenestration of a solitary nonparasitic hepatic cyst in an adult patient. ²⁵ Since that time, others have reported use of the laparoscopic technique, but mainly in case reports or small series that provide little data on long-term outcome.^3,7,11 Ardito et al. treated 47 adult patients diagnosed with nonparasitic hepatic cysts with laparoscopic fenestration due to either a symptomatic presentation or an uncertain diagnosis. None of the cases required conversion to open surgery. The overall recurrence rate was 14.9% (seven patients), yet only 4.3% (two patients) presented with recurrent symptoms that necessitated surgical management. There was no recorded postoperative mortality or morbidity, and follow-up ranged from 24 to 142 months. ²⁶ Although no randomized controlled trials are available to make definitive recommendations on laparoscopic versus open therapy, available data suggest that symptom relief and recurrence rate after laparoscopic fenestration are similar to the open approach, but with lower morbidity and mortality. ¹⁰ Also, laparoscopic fenestration has been shown to result in less pain, decreased length of hospital stay, and earlier return to normal activity when compared with open fenestration. ¹⁸

As with the open approach, recurrence has been attributed to failure to ablate the cyst lining, and failure to resect enough cyst wall to allow for adequate drainage. ²⁷ Although recurrence rates and long-term results are not known, laparoscopic fenestration is considered the standard of care for solitary nonparasitic hepatic cysts located on the liver surface.^6,10

There are limited accounts of laparoscopy being used for treatment of hepatic cysts in pediatric patients, especially in neonates, due to the limited experience of laparoscopic surgery in this patient population. ¹³ Nordin et al. reviewed all the case reports of neonatal congenital hepatic cysts in the literature and found that five out of the eight cases were managed laparoscopically, with two undergoing complete cyst excision and three undergoing fenestration. Of the reviewed cases, none reported any postoperative complications or recurrence. ²⁸ Laparoscopic surgery is associated with decreased bleeding, decreased risk of ileus, shorter hospital stay, early mobilization, and improved cosmesis.^{24, 29, 30}

Relative contraindications to the laparoscopic approach are lesions located deep inside the hepatic parenchyma and those associated with hilar structures, as these increase the risk of extensive hemorrhage or damage to bile ducts.^3,14 Laparoscopy should be reserved for lesions located in accessible areas, namely the anterior and lateral segments. ¹⁴ In the pediatric population, especially, one must consider the small working space in the abdominal cavity and the technical challenges this can present laparoscopically. Open surgical management should be reserved for cysts that are not accessible by laparoscopy. ¹⁵ Hepatic resection is appropriate for giant cysts, complex recurrent cysts, polycystic disease, diffuse liver involvement, and malignancy.^14,15 Hepatic transplantation is rarely performed for hepatic cyst disease, but it is reserved for giant cysts or polycystic disease in which resection would compromise hepatic function.