The obstruction of two or more major hepatic veins produces liver enlargement, pain, and ascites, a condition known as Budd-Chiari syndrome. Obstruction of a single main hepatic vein by thrombosis is clinically silent. Hepatic damage is the consequence of increased intrahepatic blood pressure. Hepatic vein thrombosis is associated with the same hypercoagulable states as portal vein thrombosis as well as intraabdominal cancers, particularly HCC. As is often the case in those afflicted with various thrombotic disorders, Budd-Chiari syndrome often occurs in patients with several risk factors, such as pregnancy or oral contraceptive use combined with an underlying thrombophilic disorder.
MORPHOLOGYInBudd-Chiarisyndrome,theliverisswollenandred-purpleandhasatensecapsule(
Fig.16.32 ).Theremaybeareasofhemorrhagiccollapsealternatingwithareasofpreservedorregeneratingparenchyma,dependingonwhichsmallandlargehepaticveinsareobstructed.Microscopically,theaffectedhepaticparenchymarevealsseverecentrilobularcongestionandnecrosis.Centrilobularfibrosisdevelopsininstancesinwhichthethrombosisismoreslowlydeveloping.Themajorveinsmaycontainfreshocclusivethrombior,inchroniccases,organizedadherentthrombi.
Fig. 16.32 Budd-Chiarisyndrome.Thrombosisofthemajorhepaticveinshascausedseverehepaticcongestion.
The mortality of untreated acute hepatic vein thrombosis is high. The condition is rare, and treatments are largely empiric. They include anti-coagulation to prevent clot propagation; angioplasty to restore the patency of occluded veins; thrombolysis; and creation of portovenous shunts, using either invasive radiologic approaches or surgery, in order to decompress the liver. The chronic form is far less lethal, and more than two-thirds of patients are alive after 5 years.
These hepatic manifestations of systemic circulatory compromise—passive congestion and centrilobular necrosis—are considered together because they represent a morphologic continuum. Both changes are commonly seen at autopsy, as there is an element of preterminal circulatory failure in virtually every nontraumatic death.
MORPHOLOGYRight-sidedcardiacdecompensationleadstopassivecongestionoftheliver.Theliverisslightlyenlarged,tense,andcyanotic,withroundededges.Microscopicallythereiscongestionofcentrilobular sinusoids.Withtime,centrilobularhepatocytesbecomeatrophic,resultinginmarkedlyattenuatedlivercellplates.Left-sidedcardiacfailureorshockmayleadtohepatichypo-perfusionandhypoxia,causingischemiccoagulativenecrosisofhepatocytesinthecentralregionofthelobule(centrilobular necrosis).
Thecombinationofhypoperfusionandretrogradecongestionactssynergisticallytocausecentrilobular hemorrhagic necrosis. Thelivertakesonavariegatedmottledappearance,reflectinghemorrhageandnecrosisinthecentrilobularregions(
Fig.16.33A ).Thisfindingisknownasnutmeg liver duetoitsresemblancetothecutsurfaceofanutmeg.Theretypicallyisasharpdemarcationbetweenviableperiportalandnecroticoratrophicpericentralregionsthataresuffusedwithblood(see
Fig.16.33B ).Uncommonly,withsustainedchronicseverecongestiveheartfailure,centrilobularfibrosis(cardiac sclerosis)orevencirrhosisdevelops.
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