Extrahepatic portosystemic shunt in congenital absence of the portal vein depicted by time-resolved contrast-enhanced MR angiography

The Abernethy malformation-myriad imaging manifestations of a single entity

Abernethy malformation, also known as congenital extrahepatic portosystemic shunts (CEPS) is a rare clinical entity and manifests with different clinical symptoms. CEPS are abnormalities of vascular development where there is shunting of portal blood into the systemic venous system. Multidetector computed tomography (MDCT) is a fast and effective modality for evaluation of CEPS. CT displays all the information desired by the surgeon as well as the clinician including the anatomy of the splenic and superior mesenteric veins, size and site of the shunt, presence or absence of the portal vein radicles, and helps to plan the therapy and even the follow-up of these patients. Contrast-enhanced magnetic resonance imaging (MRI) has also emerged as a promising tool for the evaluation of liver lesions associated with the malformation. The Radiologist should be aware of the various imaging appearances of this entity including its complications. In this article, we describe the imaging appearances of CEPS, their complications, and their imaging appearances on CT and MRI. We have also described various associated anomalies.

Congenital absence of the portal vein--Case report and a review of literature

Congenital absence of the portal vein (CAPV) is a rare anomaly in which the intestinal and the splenic venous drainage bypass the liver and drain into systemic veins through various venous shunts. To our knowledge, we have reviewed all 83 cases of CAPV, since first described in 1793. This equates to a rate of almost 2.5 cases per year over the last 30 years. Morgan and Superina (1994, J. Pediatr. Surg. 29:1239-1241) proposed the following classification of portosystemic anomalies; either the liver is not perfused with portal blood because of a complete shunt (Type I) or the liver is perfused with portal blood due to the presence of a partial shunt (Type II). In our case, abdominal venous blood drained into the suprarenal inferior vena cava via the left renal vein and dilated left gastric veins. After analyzing all reported cases, we recognize that more than 65% of patients are females and more than 30% of all published cases had been diagnosed by the age of 5 years. Additional anomalies are common in CAPV. In the reported cases, more then 22% of patients had congenital heart disease. Other commonly found anomalies include abnormalities of the spleen, urinary and male genital tract, brain as well as skeletal anomalies. Hepatic changes such as focal nodular hyperplasia, hepatocellular carcinoma, and hepatoblastoma are diagnosed in more then 40% of patients. This article also illustrates the radiological findings of CAPV. Radiological evaluation by ultrasound, CT, and MRI is helpful to detect coexisting abnormalities.

Congenital absence of the portal vein associated with focal nodular hyperplasia of the liver and congenital heart disease (Abernethy malformation): A case report and literature review

Abernethy malformation is a rare congenital malformation defined by an extrahepatic portosystemic shunt. The majority of affected patients are young (<18 years of age) and experience various symptoms, including vomiting, jaundice, dyspnea and coma. The current study presents a case of Abernethy malformation in an asymptomatic adult male patient. The patient exhibited congenital absence of the portal vein, congenital heart disease (postoperative ventricular septal defect status), and multiple liver lesions, confirmed to be focal nodular hyperplasia by biopsy. Ultrasonography and magnetic resonance imaging findings revealing the liver lesions, type II congenital absence of the portal vein and the portosystemic shunt are presented. In addition, the common clinical presentations, associated anomalies, diagnostic workup and treatment options of this disorder are investigated by reviewing 101 previously reported cases.

Computed tomography and magnetic resonance imaging of multiple focal nodular hyperplasias of the liver with congenital absence of the portal vein in a Chinese girl: case report and review of the literature

Background

Patients with congenital absence of the portal vein (CAPV) often suffer from additional medical complications such as hepatic tumors and cardiac malformations.

Case presentation

Congenital absence of the portal vein (CAPV) is a rare malformation. We present a case of a 16-year-old Chinese girl with CAPV with multiple pathology-proven hepatic focal nodular hyperplasias (FNHs) and ventricular septal defect (VSD). The CT and MRI features of this case are described, and previously reported cases are reviewed.

Conclusions

CAPV is a rare congenital anomaly and in such patients, clarifying the site of portosystemic shunts, liver disease, and other anomalies is critical for appropriate treatment selection and accurate prognosis determination. Close follow-up, including laboratory testing and radiologic imaging, is recommended for all CAPV patients.

Congenital portosystemic shunt: characterization of a multisystem disease

OBJECTIVES

Congenital portosystemic shunts (CPSSs) are rare but increasingly recognized as a cause of important multisystem morbidity. We present new cases and a systematic literature review and propose an algorithm for the identification and care of affected patients.

METHODS

We reviewed the charts of consecutive patients seen in our pediatric liver clinic between 2003 and 2010 and systematically reviewed the literature of cases with CPSS.

RESULTS

We identified 316 published cases and 12 patients in our own clinic. Of the published cases (177 male), 185 had an extrahepatic and 131 an intrahepatic portosystemic shunt. Diagnosis was made at any age, from prenatal to late adulthood. Cardiac anomalies were found in 22% of patients. The main complications were hyperammonemia/neurological abnormalities (35%), liver tumors (26%), and pulmonary hypertension or hepatopulmonary syndrome (18%). The spectrum of neurological involvement ranged from changes in brain imaging, subtle abnormalities on neuropsychological testing, through learning disabilities to overt encephalopathy. Spontaneous shunt closure occurred mainly in infants with intrahepatic shunts. Therapeutic interventions included shunt closure by surgery or interventional radiology techniques (35%) and liver transplantation (10%) leading to an improvement of symptoms in the majority. These findings mirror the observations in our own patients.

CONCLUSIONS

In this largest review of the reported clinical experience, we identify that children with CPSS may present with otherwise unexplained developmental delay, encephalopathy, pulmonary hypertension, hypoxemia, or liver tumors. When CPSS is diagnosed, children should be screened for all of these complications. Spontaneous closure of intrahepatic shunts may occur in infancy. Closure of the shunt is indicated in symptomatic patients and is associated with a favorable outcome.

Insight into congenital absence of the portal vein: Is it rare?

Congenital absence of portal vein (CAPV) was a rare event in the past. However, the number of detected CAPV cases has increased in recent years because of advances in imaging techniques. Patients with CAPV present with portal hypertension (PH) or porto-systemic encephalopathy (PSE), but these conditions rarely occur until the patients grow up or become old. The patients usually visit doctors for the complications of venous shunts, hepatic or cardiac abnormalities detected by ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The etiology of this disease is not clear, but most investigators consider that it is associated with abnormal embryologic development of the portal vein. Usually, surgical intervention can relieve the symptoms and prevent occurrence of complications in CAPV patients. Moreover, its management should be stressed on a case-by-case basis, depending on the type or anatomy of the disease, as well as the symptoms and clinical conditions of the patient.

The clinical anatomy of congenital portosystemic venous shunts

Congenital portosystemic venous shunts are rare. Their gross anatomy has not been well defined. Four different varieties of congenital portosystemic venous shunts are described in six children seen during a 10-year period, focusing on the anatomy of the shunt as determined by imaging studies and surgery. A detailed review of the literature indicates that congenital portosystemic venous shunts are best classified as: extrahepatic or intrahepatic. Extrahepatic shunts may be further subdivided into portocaval shunts (type 1 end-to-side and type 2 side-to-side) and others. Intrahepatic shunts are due to an abnormal intrahepatic connection between the portal vein and hepatic vein/inferior vena cava or a persistent patent ductus venosus. Additional congenital anomalies, particularly cardiac malformations, may be associated with any type. Some congenital intrahepatic portosystemic venous shunts close spontaneously in infancy; all other congenital portosystemic venous shunts tend to remain patent. To a variable extent, depending largely on the volume and duration of the shunt, affected individuals are at risk of developing hepatic encephalopathy and/or an intrahepatic tumor. The key to understanding the pathogenesis of these shunts lies in the normal developmental mechanisms underlying the formation of the portal vein and inferior vena cava in the embryo.