Case report: secondary biliary cirrhosis possibly related to congenital hepatic fibrosis. Evidence for decreased number of portal branch veins and hypertrophic peribiliary vascular plexus

Ductal Plate Malformation in the Liver of Boxer Dogs: Clinical and Histological Features

Ductal plate malformations (DPMs) represent developmental biliary disorders with a wide phenotypic spectrum. This study characterizes DPM in 30 Boxer dogs. Median age was 1.5 (range, 0.3-10.0) years, with 12 dogs <1 year. Clinical features included increased serum levels of liver enzymes (28), gastrointestinal signs (16), poor body condition (14), abdominal effusion (9), and hepatic encephalopathy (2). Additional malformations included gallbladder atresia (8), atrophied left liver (2), absent quadrate lobe with left-displaced gallbladder (1), portal vasculature atresia (left liver, 1), intrahepatic portosystemic shunt (1), and complex intrahepatic arteriovenous malformation (1). All dogs had portal tracts dimensionally expanded by a moderate-to-severe multiple small bile duct phenotype embedded in abundant extracellular matrix; 80% displayed variable portal-to-portal bridging. Quantitative analysis confirmed significantly increased fibrillar collagen and a 3-fold increased portal tract area relative to 6 Boxer and 10 non-Boxer controls. Biliary phenotype was dominated by tightly formed CK19-positive ductules, typically 10 to 15 μm in diameter, with 3 to >30 profiles per portal tract, reduced luminal apertures, and negative Ki-67 immunoreactivity. CK19-positive biliary epithelium intersected directly with zone 1 hepatocytes as a signature feature when considered with other DPM characteristics. Phenotypic variation included a multiple small bile duct phenotype (all dogs), predominantly thin-walled sacculated ducts (4), well-formed saccular ducts (4), and sacculated segmental, interlobular, and intralobular ducts (Caroli malformation, 2 dogs, one with bridging portal fibrosis). Histologic evidence of portal venous hypoperfusion accompanied increased biliary profiles in every case. We propose that this spectrum of disorders be referred to as DPM with appropriate modifiers to characterize the unique phenotypes.

Imaging findings in congenital hepatic fibrosis

Congenital hepatic fibrosis (CHF) is a rare congenital multisystemic disorder, mostly inherited in autosomal recessive fashion, primarily affecting renal and hepatobiliary systems. Main underlying process of the disease is the malformation of the ductal plate, the embryological precursor of the biliary system, and secondary biliary strictures and periportal fibrosis ultimately leading to portal hypertension. The natural course of the disease is highly variable ranging from minimally symptomatic disease to true cirrhosis of the liver. However, in most patients the most common manifestations of the diseases that are related to portal hypertension, particularly splenomegaly and bleeding varices. Many other disease processes may co-exist with the disease including Caroli's disease, choledochal cysts and autosomal recessive polycystic kidney disease (ARPKD) reflecting the mulstisystemic nature of the disease. The associating biliary ductal disease led the authors to think that all these entities are a continuum and different reflections of the same underlying pathophysiological process. Although, conventional method of diagnosis of CHF is the liver biopsy the advent of imaging technologies and modalities, today, may permit the correct diagnosis in a non-invasive manner. Characteristic imaging features are generally present and recognition of these findings may obviate liver biopsy while preserving the diagnostic accuracy. In this article, it is aimed to increase the awareness of the practising radiologists to the imaging findings of this uncommon clinical disorder and trail the blaze for future articles relating to this issue.

Cirrhosis: CT and MR imaging evaluation

In this article, we present the CT and MR imaging characteristics of the cirrhotic liver. We describe the altered liver morphology in different forms of viral, alcoholic and autoimmune end-stage liver disease. We present the spectrum of imaging findings in portal hypertension, such as splenomegaly, ascites and varices. We describe the patchy and lacelike patterns of fibrosis, along with the focal confluent form. The process of hepatocarcinogenesis is detailed, from regenerative to dysplastic nodules to overt hepatocellular carcinoma. Different types of non-neoplastic focal liver lesions occurring in the cirrhotic liver are discussed, including arterially enhancing nodules, hemangiomas and peribiliary cysts. We show different conditions causing liver morphology changes that can mimic cirrhosis, such as congenital hepatic fibrosis, "pseudo-cirrhosis" due to breast metastases treated with chemotherapy, Budd-Chiari syndrome, sarcoidosis and cavernous transformation of the portal vein.

Fibropolycystic liver disease: CT and MR imaging findings

Fibropolycystic liver disease encompasses a spectrum of related lesions of the liver and biliary tract that are caused by abnormal embryologic development of the ductal plates. These lesions (congenital hepatic fibrosis, biliary hamartomas, autosomal dominant polycystic disease, Caroli disease, choledochal cysts) can be clinically silent or can cause signs and symptoms such as cholangitis, portal hypertension, gastrointestinal bleeding, infections, and space-occupying masses. The different types of fibropolycystic liver disease demonstrate characteristic findings at computed tomography (CT) and magnetic resonance (MR) imaging. Patients with congenital hepatic fibrosis typically have imaging evidence of liver morphologic abnormalities, varices, splenomegaly, renal lesions, and other associated ductal plate abnormalities. Biliary hamartomas usually manifest as multiple cysts that are nearly uniform in size and measure up to 15 mm in diameter. Autosomal dominant polycystic disease typically manifests as an enlarged and diffusely cystic liver. In Caroli disease, cystic or fusiform dilatation of the intrahepatic ducts is seen, as well as the "central dot sign," which corresponds to a portal vein branch protruding into the lumen of a dilated bile duct. Choledochal cyst manifests as a fusiform or cystic dilatation of the extrahepatic bile duct. Awareness of these CT and MR imaging features is essential in detecting and differentiating between various fibropolycystic liver diseases and can assist in proper management.

Congenital hepatic fibrosis: CT findings in 18 adults

PURPOSE

To evaluate the computed tomographic (CT) findings in adult patients with pathologically proved congenital hepatic fibrosis.

MATERIALS AND METHODS

This was a retrospective review of congenital hepatic fibrosis cases identified at two institutions over the course of 8 years. Eight men and 10 women with an age range of 22-72 years (mean age, 39 years) were included. Contrast material-enhanced and unenhanced CT scans were obtained through the liver in all patients. Two radiologists evaluated size of and morphologic findings (atrophy or hypertrophy localized according to hepatic segments) in the liver; increased diameter or number of hepatic arteries at the hilum; presence of hepatic nodules, varices, spontaneous splenorenal shunts, and splenomegaly; and association with other hepatic ductal plate malformations and renal abnormalities.

RESULTS

Sixteen patients had morphologic abnormalities in the liver, 15 had splenomegaly (three underwent splenectomy for portal hypertension), and 14 had varices or spontaneous splenorenal shunts. An enlarged hepatic artery and a tangle of abnormally enlarged arterial vessels were identified in five and four patients, respectively, and four of these nine patients had large benign regenerative nodules. Ten patients had renal abnormalities and nine had an associated ductal plate malformation.

CONCLUSION

This retrospective study shows that certain findings (ie, liver morphologic and associated ductal plate abnormalities, varices, splenomegaly, and renal abnormalities) are frequently observed in combination in patients with congenital hepatic fibrosis.

Endothelial dysfunction in cirrhosis and portal hypertension

Portal hypertension (PHT) is a common clinical syndrome associated with chronic liver diseases; it is characterized by a pathological increase in portal pressure. Pharmacotherapy for PHT is aimed at reducing both intrahepatic vascular tone and elevated splanchnic blood flow. Due to the altered hemodynamic profile in PHT, dramatic changes in mechanical forces, both pressure and flow, may play a pivotal role in controlling endothelial and vascular smooth muscle cell signaling, structure, and function in cirrhotics. Nitric oxide, prostacyclin, endothelial-derived contracting factors, and endothelial-derived hyperpolarizing factor are powerful vasoactive substances released from the endothelium in response to both humoral and mechanical stimuli that can profoundly affect both the function and structure of the underlying vascular smooth muscle. This review will examine the contributory role of hormonal- and mechanical force-induced changes in endothelial function and signaling and the consequence of these changes on the structural and functional response of the underlying vascular smooth muscle. It will focus on the pivotal role of hormonal and mechanical force-induced endothelial release of vasoactive substances in dictating the reactivity of the underlying vascular smooth muscle, i.e., whether hyporeactive or hyperreactive, and will examine the extent to which these substances may exert a protective and/or detrimental influence on the structure of the underlying vascular smooth muscle in both a normal hemodynamic environment and following hemodynamic perturbations typical of PHT and cirrhosis. Finally, it will discuss the intracellular processes that regulate the release/expression of these vasoactive substances and that control the transformation of this normally protective cell to one that may promote the development of vasculopathy in PHT.