Hepatocellular Carcinoma in Children with Alagille Syndrome

INTRODUCTION Alagille syndrome is a well-recognized cause of neonatal cholestasis caused by paucity and hypoplasia of the intrahepatic bile ducts (1). It is associated with mutations in the Jagged1 gene on chromosome 20 (2) and carries a variable prognosis depending on the severity of the cardiac and liver disease. Most patients survive into adulthood, but some develop cirrhosis and portal hypertension. Hepatocellular carcinoma (HCC) is rare in children. It is also a rare complication of Alagille syndrome (3), with only six previous cases reported in patients less than 17 years of age (4-8). We report two 4-year-old boys with Alagille syndrome who developed HCC. CASE 1 The child, the third of three sons, presented with cholestasis as a neonate and was diagnosed with Alagille syndrome at 3 months of age. The diagnosis was based on a typical facies (broad forehead, deep-set, widely spaced eyes, long straight nose, and an underdeveloped mandible) and hemodynamically insignificant peripheral pulmonary artery stenosis. He did not have butterfly vertebrae or posterior embryotoxon. There was no family history of the syndrome. Initial treatment with fat-soluble vitamins and ursodeoxycholic acid produced no significant improvement in cholestasis. He developed progressive splenomegaly over the next 3 years suggestive of portal hypertension. Severe pruritus was partially alleviated by therapy with rifampicin. He was developmentally normal and demonstrated good growth (weight 90th percentile, height 90th percentile). At 4 years of age, a routine abdominal ultrasound demonstrated unchanged hepatosplenomegaly with no focal hepatic parenchymal lesion. Over the next 4 months, he began to experience intermittent fevers and worsening upper respiratory symptoms, requiring several courses of oral antibiotics with only temporary symptomatic improvement. One week before presentation, he developed increased abdominal distension, respiratory distress, and low-grade fever. He was more lethargic than usual, and jaundice and pruritus were more pronounced. Physical examination on admission to hospital showed marked jaundice, a firm nontender liver palpable 6 cm below the right costal margin, a spleen palpable at the umbilicus, and ascites. Laboratory tests showed an unchanged degree of cholestasis with evidence of liver synthetic dysfunction: bilirubin total 506 μmol/L (29 mg/dL), bilirubin direct 429 μmol/L (25 mg/dL), aspartate transaminase 279 U/L, alanine transaminase 94 U/L, gamma-glutamyl transferase 233 U/L, alkaline phosphatase 241 U/L, ammonia 67 μmol/L (114 g/dL), albumin 26 g/L (2.6 g/dL), International Normalized Ratio (INR) 1.3, hemoglobin 105 g/L (10.5 g/dL), platelets 246 × 109/L, and neutrophils 2.0 × 109/L. Abdominal ultrasound suggested the presence of a mass in the right lobe of the liver and thrombus in the left portal vein. A computerized tomography (CT) scan confirmed a large 14 × 10 cm heterogeneous mass in the right lobe of the liver and two pulmonary metastases (Fig. 1). Serum alpha-fetoprotein (AFP) was 264,200 IU/mL (normal <6 IU/mL). Ultrasound-guided percutaneous liver biopsy was performed, and histology confirmed a moderately differentiated HCC without definite evidence of cirrhosis (Fig. 2).FIG. 1: Postcontrast computed tomography. Axial section of the upper abdomen shows a bilobulated low-density intrahepatic mass lesion in the right lobe of the liver with portal vein invasion.FIG. 2: Moderately differentiated hepatocellular carcinoma with nodules of pleomorphic small hepatocytes showing loss of trabecular pattern, focal steatosis, a high nuclear/cytoplasmic ratio and nuclear pseudoinclusions (hematoxylin-eosin, magnification × 40).Because of the size of the primary tumour, the presence of lung metastases, and tumour thrombus of the portal vein, liver transplantation was not a feasible option. The oncologic service felt that chemotherapy would not be of any long-term benefit and might have significant adverse short-term effects on the child's quality of life. The family decided not to pursue further treatment. Two weeks after presentation, he died peacefully, having become increasingly encephalopathic, at least partly because of occlusion of the portal vein from tumour thrombus. CASE 2 This boy presented with cholestasis as a neonate. The diagnosis of Alagille syndrome was based on the typical facies, branch pulmonary artery stenosis, radiologic evidence of a thoracic butterfly vertebra, and ultrasound evidence of a horseshoe kidney with loss of renal corticomedullary differentiation. His father and his father's sister had Alagille syndrome, and the sister had died of her associated congenital heart disease at 16 years of age. Despite extensive analysis, no mutations in Jagged1 were identified. Initial treatment included fat-soluble vitamins. He became anicteric at age 6 months, and supplemental vitamins were discontinued. He also received antihistamines for persistent pruritus, and, at age 2, atorvastatin (a HMG-CoA reductase inhibitor) was prescribed for hypercholesterolemia. He maintained linear growth along the third percentile with normal development. His liver and spleen gradually enlarged, and hepatic ultrasounds and serum AFP measurements were performed at regular intervals. At age 3, his AFP was noted to be elevated at 786 IU/mL (normal <6 IU/mL), and abdominal CT demonstrated an isoechoic mass in segment 4 of the liver. A percutaneous biopsy of the mass was performed, and histologic examination described it as a regenerating nodule with no evidence of malignancy. Subsequent AFP levels and ultrasound were unchanged 6 months later. At age 4, the AFP was 8,155 IU/mL (normal <6 IU/mL) with otherwise unchanged laboratory values including bilirubin total 27 μmol/L (1.55 mg/dL), bilirubin direct 21 μmol/L (1.22 mg/dL), aspartate transaminase 311 U/L, alanine transaminase 228 U/L, gamma-glutamyl transferase 236 U/L, alkaline phosphatase 892 U/L, albumin 39 g/L (3.9 g/dL), INR 1.0, hemoglobin 108 g/L (10.8 g/dL), platelets 263 × 109/L, and neutrophils 4.4 × 109/L. CT demonstrated a 2 × 2 cm mass in segment 6 of the liver. Laparotomy and wedge resection of the mass was performed, and histology confirmed a moderately differentiated HCC with clear margins, extensive fibrosis, and early cirrhosis. A repeat biopsy of the original lesion in segment 4 showed no histologic evidence of malignancy. A chest CT scan showed no evidence of metastatic spread, and repeated scans remained clear, with the AFP level rapidly returning to normal. Given the successful surgical resection of the HCC, the subsequent normal AFP levels, imaging studies suggesting disease remission, and the high probability of tumour recurrence (9), he underwent orthotopic liver transplantation. He received a split graft liver transplant. The postoperative course was complicated by a bile leak and subsequent biliary cast requiring revision of the biliary anastomosis. He unexpectedly died 3 months after transplant from Eschericia coli septicemia. At postmortem examination, there was no evidence of tumor recurrence. DISCUSSION Alagille syndrome is an inherited disorder with an autosomal dominant mode of transmission and variable expressivity. Estimates of prevalence range from 1 in 40,000 to 1 in 100,000 live births, and the condition occurs in all ethnic groups. Features include cholestatic liver disease caused by paucity of intrahepatic bile ducts, typical facies, cardiovascular and ophthalmological abnormalities, vertebral defects, and tubulointerstitial nephropathy. Other occasional abnormalities include growth retardation, high-pitched voice, intellectual disability, and hypogonadism. Significant contributors to mortality (as percentage of deaths) include complex congenital heart disease (15%), intracranial bleeding (25%), and hepatic disease (25%), but overall, the 20-year predicted life expectancy is 75% for all patients (10). HCC has been reported as a complication of Alagille syndrome in 6 children (4-8) and 10 adults (3,6,11-18). The reported pediatric cases are in two distinct age groups: four in early childhood (age 2-4) (4-6,8) and two in adolescence (age 16-17) (6,7). The early childhood cases experienced prominent pruritus, and all had histologically confirmed cirrhosis at biopsy or postmortem. Our cases generally conformed to this pattern of presentation. Although case 1 did not have cirrhosis histologically, the needle biopsies were largely confined to the tumor. In addition, this patient had had portal hypertension and hypersplenism for 2 to 3 years before tumor occurrence, suggesting the presence of cirrhosis. HCC is an uncommon tumour in the pediatric age group. Most of the reported cases have an underlying cirrhosis, which presumably predisposes to the development of malignancy. The majority of individuals with Alagille syndrome have mutations in the Jagged1 gene, which encodes a cell surface ligand for the Notch receptor. Signals transmitted through the Notch receptor, in combination with other cellular signals, control cell fate, including differentiation, proliferation, and apoptosis during development. Recent evidence suggests a role for the Notch signaling pathway in neoplastic transformation, as a downstream effector of oncogenic Ras (19). This has not previously been described in hepatocytes but has been reported in cervical neoplasms (20), squamous cell carcinomas of the head and neck (21), renal cell carcinoma (22), and acute myeloid leukemia (23). The early development of HCC in our patients, regardless of the presence or not of cirrhosis, could be a reflection of a deregulated cell fate pathway consequent to disrupted Notch signaling. The apparent low incidence of HCC in Alagille syndrome could represent genotypic-phenotypic variability whereby specific mutations in the gene may predispose to the development of malignancy. The previous reports of HCC have suggested that patients with Alagille syndrome should undergo regular screening with ultrasound and/or CT and serum AFP measurements (4-7), with the aim of detecting the development of liver tumors before metastatic spread has occurred. These cases would then be candidates for primary resection of the tumor or orthotopic liver transplantation. However, the optimal frequency of such investigations is unclear, as for instance in case 1 where the tumour developed within 4 months of an ultrasound that had demonstrated no apparent hepatic parenchymal lesion. A rising serum AFP over an interval of 6 months led to the early recognition of HCC in case 2, but one has to be aware that raised AFP levels can be seen with liver regeneration as well as HCC (24). We suggest that there be a high index of suspicion for the development of HCC in young patients with Alagille syndrome, particularly in those with jaundice, pruritus, and cirrhosis. Screening could be undertaken with serum AFP measurements and hepatic imaging studies, using either ultrasound, CT, or magnetic resonance imaging. However, the exact modality of screening and the frequency of testing required to prevent the development of HCC remains to be determined. Acknowledgment The authors thank Dr. Ramanand Kamath for his comments and suggestions on the manuscript.