he had a history of neonatal hepatitis and had been diagnosed with congenital ipsvs six years before . the shunt was not corrected at that time because his parents were concerned about the possible complications associated with the therapeutic procedure . currently , the boy is under medication for attention - deficit hyperactivity disorder . laboratory values have shown a prolonged coagulation profile and slightly elevated ammonia level : prothrombin time , 20.1 sec ; inr ( international normalized ratio ) , 2.02 ; and ammonia , 55 umol / l . abdominal ultrasonogram ( us ) demonstrated anechoic tubular structures connecting the left portal vein and the dilated left hepatic vein with a small - sized right portal vein . color doppler imaging revealed high - velocity , continuous waveform through the shunt ; which are consistent with ipsvs . enhanced computed tomography ( ct ) confirmed the sonographic findings . three , variably - sized tubular vessels connected the left portal vein and the left hepatic vein , forming a loop - like appearance . in the liver 's right lobe , we found a 3.5-cm sized mass , which showed heterogeneous nodular enhancement on the arterial phase and a mostly prolonged enhancement on five - minute delayed images ( fig . we thought it was possibly a benign tumor such as hemangioendothelioma or focal nodular hyperplasia ( fnh ) , but we could not exclude a malignancy . the patient 's parents did n't want their child to undergo an invasive procedure for the ipsvs ; thus , the pediatrician decided to conduct a close follow - up . at six - month follow - up , the boy 's blood ammonia level had risen to 94 umol / l , which is four times the normal range . a follow - up ct scan showed no significant change in the ipsvs and hepatic mass . shunt ratio was calculated through the doppler us ( 8) , by dividing the blood flow volume at the shunt orifice ( 814 cc / min ) by the total portal blood flow volume ( 882 cc / min ) . the shunt ratio was 92% , so we thought that the patient 's condition could progress to hepatic encephalopathy . therefore , we decided to close the shunt via endovascular treatment . under general anesthesia , an us - guided transhepatic right portal vein puncture was performed using a 22 g needle , followed by the insertion of a 7 fr , 24 cm sheath ( super arrow - flex : arrow , pa ) . a direct portogram showed that the dilated left portal vein was connected directly with the dilated left hepatic vein by three variable tubular shunt channels ( fig . the right portal vein was very small compared to the left ; hence , we chose to treat the boy with an amplatzer vascular plug ( avp ; aga medical , mn ) because of the shunt 's large size . a 20-mm avp was deployed into the distal part of the largest shunt channel and two 12 mm avps were placed on the other smaller shunt channels . a post - embolization portography identified the absence of blood flow through the shunts and increased flow in the right portal vein ( fig . as we withdrew the sheath , we injected thick gelfoam slurry through the sheath 's tract to avoid intra - abdominal bleeding . however , the patient 's blood pressure suddenly dropped to 60/30 mmhg during the compression of the puncture site . he experienced transient hypovolemic shock , but improved within 24 hours and recovered fully without further complication . six days after the procedure , the patient 's serum ammonia level had decreased to within the normal range ( 25 umol / l ) , and was discharged nine days post - embolization . an abdominal us performed two weeks later , showed occluded shunts and a slight decrease in the size of the hepatic mass . the right portal vein 's blood flow had increased markedly with decreased main portal flow and minimally increased spleen size . a follow - up ct scan a month later showed complete embolization of the ipsvs along with improved portal flow to the right lobe ( fig . a congenital ipsvs is rare anomaly that results from abnormal embryologic development of the vitelline vein , or a variety of persistent patent ductus venosus ( 3 , 6 ) . in patients with congenital ipsvs early diagnosis is important , even though patients can be asymptomatic , because the shunt 's persistent patency causes hyperammonemia and increases the risk of hepatic encephalopathy ( 1 , 9 , 10 ) . intrahepatic portosystemic venous shunt must be treated in patients with hepatic encephalopathy . in asymptomatic cases , if the shunt ratio exceeds 60% , treatment is needed , even without hepatic encephalopathy ( 11 ) . our patient 's shunt ratio was extremely high and his blood ammonia level was four times the normal range ; thus , we decided on a therapeutic intervention . aside from dietary control , surgical operations such as shunt ligation and hepatic resection were performed in the past years ( 1 , 4 ) . previous reports describe several percutaneous techniques for treating these shunts using various embolic agents and variable approach routes ( 5 , 6 , 12 ) . however , we believe that our patient 's shunts were too large to embolize with coils or other embolic agents , because of the potential complications of migration . our patient displayed mild splenomegaly ; however , the size of the spleen did not differ significantly between the imaging studies performed two and four weeks after embolization . considering the right portal vein 's growth , we do n't expect portal vein hypertension to progress ; however , the boy will need additional close follow - up . to our knowledge , no reported cases of congenital ipsvs have been treated by avp , which can be used to occlude large , high - flow vessels . recent reports do exist about the use of this device , other than the first introduced era ( 14 , 15 ) . unlike embolization coils , an avp can be positioned accurately , and migration of the avp is uncommon . in the present case , we successfully occluded the large shunt using avps with clinical success and without avp - related complications . the bleeding episode , following shunt embolization in our patient , occurred through the sheath tract . a shunt occlusion must lead to an increase in blood flow and pressure in the right portal vein , and our method of tract embolization was insufficient for hemostasis . transparenchymal tract embolization with different embolic agents including coils , gelfoam , and glue have been reported in cases of transhepatic portal vein approach or biopsy ( 16 - 19 ) . an appropriate method must be chosen by considering the hemodynamic change after the procedure . moreover nodular liver lesions associated with congenital portosystemic shunts are not a rare condition ( 4 , 20 ) . most of these lesions such as fnh or nodular regenerative hyperplasia , are benign ( 4 ) . regenerative liver lesions have been attributed to the diminution of portal flow and compensatory increase in hepatic arterial flow . the increased levels of hepatic growth factors through systemic circulation are also regarded as causative ( 4 ) . because the regenerative nodules are well described in congenital portosystemic shunts ; and , because of the bleeding risk associated with a biopsy due to the hypervascular nature of ct scans , we decided to conduct a follow - up evaluation of the patient 's mass lesion ( 21 ) . our patient 's mass had been dramatically reduced after just a short follow - up period , which led us to conclude that the mass was most likely benign because of the increased portal flow to liver 's right lobe , as described earlier ( 4 ) . in conclusion , ipsvs occlusion with an avp is safe and effective , and shunt occlusion is a beneficial treatment method for regenerative liver lesions , as well as decreasing the risk of hepatic encephalopathy .
a congenital intrahepatic portosystemic shunt is a rare anomaly ; but , the number of diagnosed cases has increased with advanced imaging tools . 
 symptomatic portosystemic shunts , especially those that include hyperammonemia , should be treated ; and various endovascular treatment methods other than surgery have been reported . 
 hepatic masses with either an intra- or extrahepatic shunt also have been reported , and the mass is another reason for treatment . 
 authors report a case of a congenital intrahepatic portosystemic shunt with a hepatic mass that was successfully treated using a percutaneous endovascular approach with vascular plugs . by the time the first short - term follow - up was conducted 
 , the hepatic mass had disappeared .