Portal vein thrombosis may result from perinatal omphalitis, cannulation of the umbilical vein, intraabdominal sepsis, or dehydration, but in more than half the cases, no etiologic event is discovered (1). Regardless of its cause, preexisting periportal and paracholedochal vessels enlarge, and hepatopetal blood flow results in collateral circulation (2). Bleeding is the most common and major complication of this pathologic process. Collaterals can also cause extrinsic compression of the extrahepatic biliary tract, whose radiologic appearance has been named a pseudocholangiocarcinoma sign in adults (3). The English language literature consists of a few cases (4,5) on this rare complication of collateral circulation, in which accurate diagnosis and treatment is a challenge. Herein, we present the first childhood case of pseudocholangiocarcinoma associated with hepatoblastoma. Considerations in clinical and radiologic diagnosis and surgical management are discussed.
A 3-year-old boy was referred to our unit for further investigation with the presumptive diagnosis of hepatic malignancy. The physical examination findings revealed hepatomegaly with a discrete mass in the right upper quadrant extending to the midline. Anorexia, weight loss, vomiting, and abdominal pain were the other symptoms, which had been noted for the last 2 months. Complete blood count and kidney function test results were normal. Liver function tests showed elevated serum levels of direct reacting bilirubin and alkaline phosphatase. Abdominal ultrasound scan showed multiple solid masses located in the right lobe of liver. Computerized tomography of the thorax and abdomen confirmed the hepatic masses (Fig. 1) and showed nodular metastases in the lungs as well. The diagnosis of hepatoblastoma (epithelial type) was made by truecut biopsy of the liver. The alpha-fetoprotein level was found to be elevated to 705 μg/L. A chemotherapy regimen consisting of cyclophosphamide, carboplatin, and etoposide was commenced. Chemotherapy reduced the size and number of the tumors by as much as 70%. Angiography was performed before surgery to identify the vascular anomalies and extension of the residual tumor into the vascular structures (Fig. 2A). Cavernous transformation of the portal vein was noted during the venous phase (Fig. 2B). The patient had no history of etiologic factors (i.e., omphalitis, exchange transfusion, severe dehydration, etc.) that might have caused extrahepatic portal hypertension, portal vein thrombosis, or both. The spleen was normal both on physical and radiologic examinations.
At operation, a residual tumor of 5 × 3 × 3 cm located in the right lobe was found. There were no dilated veins in the mesentery or over the anterior surface of the liver, esophagus, and stomach. The spleen and splenic vessels were normal. However, there were numerous dilated tortuous veins measuring 4 to 10 mm in diameter on the anterior and posterior surface of the common bile duct. These thin-walled veins filled from both the cranial and caudal end of the hepatoduodenal ligament. Although several variceal cords were ligated to provide a suitable site for the choledochal exploration, the extrahepatic biliary tract could not be visualized satisfactorily. Therefore, right lobectomy was performed with great difficulty. Cholangiography was performed intraoperatively to confirm the patency of the biliary tract after lobectomy. It revealed an irregular narrowing and severe angulation of the bile duct, the so-called pseudocholangiocarcinoma sign (Fig. 3). The patient made an uneventful recovery was and referred to the pediatric oncology unit for further follow-up.
Cavernous transformation of the portal vein represents recanalization of the occluded portal vein caused by various diseases (6). Development of extensive collateral veins rarely compresses the biliary tract, resulting in obstructive jaundice (4,5), but usually presents as a surgical hazard (7). The paracholedochal and epicholedochal veins constitute the main venous systems along the extrahepatic biliary tract (3). The epicholedochal venous system is a fine reticular mural structure in close contact with the outer surface of the common bile duct. Dilatation of the plexus alters the normally smooth intraluminal surface of the common duct and produces irregular mural changes. Paracholedochal veins that are separate structures from the bile ducts cause extrinsic impressions. The dilatation of these venous systems is called bile duct varices and causes narrowing, the irregularity, and the nodular extrinsic compression of the extrahepatic biliary tract, suggesting cholangiocarcinoma. Therefore, a new nomenclature, the pseudocholangiocarcinoma sign, was proposed by Bayraktar et al. (3), although cholangiographic demonstration of the bile duct varices was made 10 years before the proposal of the nomenclature (8).
To the best of our knowledge, all patients, including the unique childhood case (5), had portal hypertension as the cause of bile duct varices. Indeed, disappearance of the pseudocholangiocarcinoma sign after reducing the pressure of portal vein by transjugular intrahepatic portosystemic shunt has been demonstrated (9). Therefore, the present case is unique with regard to underlying pathologic features. We did not encounter any other cases with an association of hepatoblastoma and pseudocholangiocarcinoma phenomenon during an extensive literature review. Although the literature consists of reports in which hepatoblastoma and portal vein thrombosis coexist (10,11), in none of the cases was the pseudocholangiocarcinoma sign noted.
Our patient also had the laboratory characteristics of the pseudocholangiocarcinoma sign by the elevated serum levels of direct reacting bilirubin and alkaline phosphatase (12). Similar laboratory and cholangiographic findings can be seen in cases of extrinsic tumors compressing the biliary tract, parasitic organisms, chronic cholangitis, chronic pancreatitis, primary sclerosing cholangitis, and particularly cholangiocarcinoma (6). No attacks of cholangitis or any other evidence of disease were noted in the present case.
Although it is very difficult to prove a causative relation between hepatoblastoma and the pseudocholangiocarcinoma sign, the temporal relation certainly raises questions of causation. Extensive invasion of the portal vein by the tumor or a resolved portal vein thrombus that could not be initially detected by radiologic examinations may have been the etiologic factor. One can even speculate about the role of angiogenic factors secreted by the tumor for the development of bile duct varices (13). In the present case, there were no signs or symptoms related to portal hypertension either on physical and radiologic examinations or at the time of surgery. Cavernous transformation was thought to be idiopathic. Thus, the association of hepatoblastoma and idiopathic cavernous transformation can be considered to be coincidental. Because both of them are relatively common entities during childhood, the possibility of coincidence seems feasible.
Based on literature review and our experience, we emphasize that the pseudocholangiocarcinoma phenomenon should be considered in children with liver tumors, portal hypertension, or both at presentation. Bile duct varices causing this phenomenon complicate surgical intervention, result in obstructive jaundice, or both.
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