Congenital extrahepatic portosystemic shunt masquerading as chronic portal vein thrombosis: A case report

INTRODUCTION AND IMPORTANCE: Congenital extra hepatic portosystemic shunt (CEPS) is a rare vascular malformation in which splanchnic and portal blood is shunted into the systemic circulation eluding the liver. Type 1 CEPS is sometimes difficult to differentiate from pathologies such as chronic portal veinthrombosis as the portal vein may not be visualized in either entities. CASE PRESENTATION: A 3-year-old male child with a week of abdominal pain was diagnosed with chronic portal vein thrombosis in an out-of-hospital setting. Repeat abdominal ultrasound was done at our institution and we were able to visualize termination of the portal vein to the suprarenal infra-hepatic inferior vena cava with an end to side pattern and a focal hypoechoic hepatic lesion at segment eight of the liver. There was no evidence of cavernous transformation or sign of portal hypertension. Subsequently, tri-phasic computed tomography revealed similar findings, with the portal vein terminating at the suprarenal inferior vena cava. The focal hepatic lesion showed peripheral contrast enhancement in the arterial phase and appeared as a central non-enhancing area with evidence of homogeneous enhancement on the subsequent sequences. CLINICAL DISCUSSION: Type 1 CEPS can be easily confused with chronic portal vein thrombosis as the portal vein may not be visible and the hepatic artery shows compensatory enlargement in both entities. However, portal vein thrombosis is usually associated with underlying predisposing factors and can result in the development of secondary signs of portal hypertension and cavernous transformation which are critical to distinguish it from CEPS. CONCLUSION: Chronic portal vein thrombosis is a great mimicker that should be distinguished from CEPS on ultrasound. A meticulous scan with color flow is helpful to scrutinize vascular anatomy, identify findings associated with CEPS such as hepatic lesions, and exclude signs of chronic portal vein thrombosis.