Magnetic Resonance Imaging of Fibropolycystic Liver Disease: The
Total Page：16
File Type：pdf, Size：1020Kb
Abdominal Radiology (2019) 44:2156–2171 https://doi.org/10.1007/s00261-019-01966-9 REVIEW Magnetic resonance imaging of fbropolycystic liver disease: the spectrum of ductal plate malformations Giuseppe Mamone1 · Vincenzo Carollo1 · Kelvin Cortis2 · Sarah Aquilina2 · Rosa Liotta3 · Roberto Miraglia1 Published online: 9 March 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Fibropolycystic liver diseases, also known as ductal plate malformations, are a group of associated congenital disorders resulting from abnormal development of the biliary ductal system. These disorders include congenital hepatic fbrosis, biliary hamartomas, polycystic liver disease, choledochal cysts and Caroli disease. Recently, it has been thought to include biliary atresia in this group of diseases, because ductal plate malformations could be implicated in the pathogenesis of this disease. Concomitant associated renal anomalies can also be present, such as autosomal recessive polycystic kidney disease (ARPKD), medullary sponge kidney and nephronophthisis. These disorders can be clinically silent or can cause abnormalities such as cholangitis, portal hypertension, gastrointestinal bleeding and infections. The diferent types of ductal plate malformations show typical fndings at magnetic resonance (MR) imaging. A clear knowledge of the embryology and pathogenesis of the ductal plate plays a pivotal role to understand the characteristic imaging appearances of these complex diseases. Awareness of these MR imaging fndings is central to the detecting and diferentiating between various fbropolycystic liver diseases and is important to direct appropriate clinical management and prevent misdiagnosis. Keywords Fibropolycystic liver diseases · Ductal plate malformations · Magnetic resonance imaging Introduction liver histology in patients with this disease. Ductal plate malformations can exist as individual conditions or in vari- Fibropolycystic liver diseases represent a complex contin- ous combinations, suggesting the expression of a common uum of pathological abnormalities that are thought to arise underlying genetic abnormality. The clinical manifestations from a derangement of embryonic ductal plate development vary widely and include hepatic fbrosis, cholangitis, portal at various stages [1, 2]. hypertension and renal anomalies [1, 2]. These abnormalities include congenital hepatic fbrosis, Magnetic resonance (MR) imaging plays a pivotal role, biliary hamartomas, polycystic liver disease, Caroli dis- allowing a noninvasive accurate detection and diferentiation ease, choledochal cysts and probably biliary atresia, since of these disorders [3] and facilitating patient management. ductal plate malformation features have been reported on The aim of this paper is to show the importance of know- ing the embryological aspects of the fbropolycystic liver disease, to describe the MR imaging features of the spectrum * Giuseppe Mamone of ductal plate malformations and also to discuss the relevant [email protected] diferential diagnosis of these entities. 1 Radiology Unit, Department of Diagnostic and Therapeutic Services, IRCCS ISMETT (Mediterranean Institute for Transplantation and Advanced Specialized Therapies), Ductal plate embryologic development Via Tricomi 5, 90127 Palermo, Italy 2 Department of Medical Imaging, Mater Dei Hospital, The ductal plate is a transient structure and consists of a Msida MSD 2090, Malta double cylinder of hapatoblasts surrounding portal vein 3 Pathology Unit, Department of Diagnostic and Therapeutic branches, that develops during the embryonic life (Fig. 1). Services, IRCCS ISMETT (Mediterranean Institute The hepatoblasts are bipotential cells and are capable of for Transplantation and Advanced Specialized Therapies), diferentiating into hepatocytes or cholangiocytes (bile Via Tricomi 5, 90127 Palermo, Italy Vol:.(1234567890)1 3 Abdominal Radiology (2019) 44:2156–2171 2157 Fig. 2 Etiology of ductal plate malformations. The process of remod- eling and partial involution occurs during the embryonic life, begin- ning from the hilum to the periphery of the liver with successive Fig. 1 Biliary ducts embryologic development. The ductal plate development of initially the larger ducts, the segmental ducts, the is a transient structure and consists of a double cylinder of hapato- interlobular ducts and fnally the smallest bile ductules. The alteration blasts (green circles) surrounding portal vein branches (blue circle), of this process can result in ductal plate malformations and the level that develops during the embryonic life. Biliary ducts are normally of involvement determines the clinical and radiopathological manifes- formed from remodeling and partial involution of these cylindric tations. Recently, it has been thought to include biliary atresia in this ductal plates. The alteration of this process can result in ductal plate group of diseases, because ductal plate malformations could be impli- malformations cated in the pathogenesis of this disease duct cells) [2, 3]. Biliary diferentiation occurs when the Involvement of small-sized intra-hepatic duct results in embryonic cells are in contact with the mesenchyme sur- biliary hamartomas and congenital hepatic fbrosis. Further- rounding the portal vein ramifcations. This cell layer joins more, the intra-hepatic biliary duct system is still immature with a second layer to create a double epithelial cylinder of at birth, with fnal development of the smallest ramifcations primitive biliary cells called “ductal plate” [2, 3]. during the frst few neonatal weeks; this condition makes Biliary duct development results from remodeling and them susceptible to noxious stimuli even during neonatal partial involution of this ductal plate. In fact, some seg- period [4]. ments of the cylindrical lumen undergo dilation, forming Some authors think that hormones could play a role in tubular structures that are gradually incorporated into the this pathological process. Estrogen receptors are expressed portal mesenchyme, and the residual nontubular segments in the epithelium lining the hepatic cysts and estrogens stim- of the ductal plate disappear by apoptosis [2]. ulate hepatic cyst-derived cell proliferation. This explains This remodeling and partial involution occurs during why in policystic liver disease the hepatic cysts are more the embryonic life to form bile canaliculi of various sizes, prevalent and hepatic cyst volume is larger in women than beginning from the hilum to the periphery of the liver in men and why women who have had multiple pregnancies with successive development of initially the larger ducts, or used oral contraceptive agents or estrogen replacement the segmental ducts, the interlobular ducts and fnally the therapy have worse disease than those who have not [5]. smallest bile ductules [2–4] (Fig. 2). The alteration of this Given that fbropolycystic liver diseases arise from the same process can result in ductal plate malformations and the pathological process resulting from abnormal embryogen- level of involvement determines the clinical and radio- esis of the biliary ductal system, it is important to understand pathological manifestations, and also the level of fbrosis, that together these disorders form a spectrum and can exist with fbrosis being a dominant feature with small duct as an individual conditions or in various combinations in involvement. the same patient. Malformations of the large extra-hepatic biliary ducts result in choledochal cysts, although controversy remains regarding this pathogenesis. Congenital hepatic fbrosis Caroli disease is characterized by ductal plate malfor- mation of the large intrahepatic bile ducts. Involvement of Congenital hepatic fbrosis is an autosomal recessive devel- medium-sized intra-hepatic ducts results in autosomal-dom- opmental disorder that belongs to the family of hepatic inant polycystic liver disease (ADPLD). ductal plate malformations and characterized histologically 1 3 2158 Abdominal Radiology (2019) 44:2156–2171 by a variable degree of periportal fbrosis (Fig. 3) and irregu- homogeneously hyperattenuating on hepatic arterial and larly shaped proliferating bile ducts, which progresses over portal venous phase without wash-out, and isointense on time [4, 6, 7]. Clinico-pathologic features of this disorder are hepatobiliary phase (Fig. 5), simulating focal nodular hyper- non-specifc, making radiology an important tool in diagnos- plasia (FNH) and regenerative nodular hyperplasia (RNH). ing this condition. Indeed, all together, these lesions show similar fndings on Portal hypertension is usually the frst manifestations of imaging and pathology, but FNH occurs in healthy liver and the disease, with splenomegaly, varices and spontaneous the defnition of “nodular regenerative hyperplasia” implies gastrointestinal bleeding. that no fbrosis is present between the nodules [12]. For this Onset of disease is variable from early childhood to the reason, in our opinion nodules encountered in patients with 5-6th decade of life, although in most patients the disor- congenital hepatic fbrosis are better defned as FNH-like der is diagnosed in adolescents or young adults [7]. These regenerative nodules, owing to the presence of fbrosis in the patients show liver function tests normal or only modestly surrounding liver and the potential progression to cirrhosis elevated. Some radiological fndings of congenital hepatic [12]. The 50% of patients with congenital hepatic fbrosis fibrosis are reported [8]. Atrophy