Cystic dilatation of peribiliary glands in livers with adult polycystic disease and livers with solitary nonparasitic cysts: an autopsy study

Management of benign liver tumors

Benign liver tumors in children are far less frequent than their malignant counterparts. Recently, there have been advances of diagnostic procedures and novel treatments with improved classification as a result. While malignant pediatric liver tumors have been comprehensively addressed by multicenter international tumor trials, benign tumors have more usually relied upon individualised workup and treatment. Due to the rarity and heterogeneity of these different entities, large studies are lacking. In this article the authors highlight the spectrum of benign liver tumors with special focus on specific clinical features, pathology, and treatment.

Gallbladder wall abnormality in biliary atresia of mouse Sox17+/- neonates and human infants

Biliary atresia (BA) is characterized by the inflammation and obstruction of the extrahepatic bile ducts (EHBDs) in newborn infants. SOX17 is a master regulator of fetal EHBD formation. In mouse Sox17+/- BA models, SOX17 reduction causes cell-autonomous epithelial shedding together with the ectopic appearance of SOX9-positive cystic duct-like epithelia in the gallbladder walls, resulting in BA-like symptoms during the perinatal period. However, the similarities with human BA gallbladders are still unclear. In the present study, we conducted phenotypic analysis of Sox17+/- BA neonate mice, in order to compare with the gallbladder wall phenotype of human BA infants. The most characteristic phenotype of the Sox17+/- BA gallbladders is the ectopic appearance of SOX9-positive peribiliary glands (PBGs), so-called pseudopyloric glands (PPGs). Next, we examined SOX17/SOX9 expression profiles of human gallbladders in 13 BA infants. Among them, five BA cases showed a loss or drastic reduction of SOX17-positive signals throughout the whole region of gallbladder epithelia (SOX17-low group). Even in the remaining eight gallbladders (SOX17-high group), the epithelial cells near the decidual sites were frequently reduced in the SOX17-positive signal intensity. Most interestingly, the most characteristic phenotype of human BA gallbladders is the increased density of PBG/PPG-like glands in the gallbladder body, especially near the epithelial decidual site, indicating that PBG/PPG formation is a common phenotype between human BA and mouse Sox17+/- BA gallbladders. These findings provide the first evidence of the potential contribution of SOX17 reduction and PBG/PPG formation to the early pathogenesis of human BA gallbladders.This article has an associated First Person interview with the joint first authors of the paper.

Polycystic kidney and hepatic disease 1 gene mutations in von Meyenburg complexes: Case report

Von Meyenburg complexes (VMCs) are a rare type of ductal plate malformation. We herein report two Chinese families with VMCs, and the suspicious gene mutation of this disease. Proband A was a 62-year-old woman with abnormal echographic presentation of the liver. She received magnetic resonance imaging (MRI) examination and liver biopsy, and the results showed she had VMCs. Histologically proved hepatocellular carcinoma was found 1 year after the diagnosis of VMCs. Proband B was a 57-year-old woman with intrahepatic diffuse lesions displayed by abdominal ultrasonography. Her final diagnoses were VMCs, congenital hepatic fibrosis, and hepatitis B surface e antigen-negative chronic hepatitis B after a series of examinations. Then, all the family members of both proband A and proband B were screened for VMCs by MRI or ultrasonography. The results showed that four of the 11 family members from two families, including two males and two females, were diagnosed with VMCs. DNA samples were extracted from the peripheral blood of those 11 individuals of two VMCs pedigrees and subjected to polymerase chain reaction amplification of the polycystic kidney and hepatic disease 1 (PKHD1) gene. Two different mutation loci were identified. Heterozygous mutations located in exon 32 (c.4280delG, p.Gly1427ValfsX6) in family A and exon 28 (c.3118C>T, p.Arg1040Ter) in family B were detected. We speculate that PKHD1 gene mutations may be responsible for the development of VMCs.

Histopathology of a benign bile duct lesion in the liver: Morphologic mimicker or precursor of intrahepatic cholangiocarcinoma

A bile duct lesion originating from intrahepatic bile ducts is generally regarded as an incidental pathologic finding in liver specimens. However, a recent study on the molecular classification of intrahepatic cholangiocarcinoma has focused on the heterogeneity of this carcinoma and has suggested that the cells of different origins present in the biliary tree may have a major role in the mechanism of oncogenesis. In this review, benign intrahepatic bile duct lesions—regarded in the past as reactive changes or remnant developmental anomalies and now noted to have potential for developing precursor lesions of intrahepatic cholangiocarcinoma—are discussed by focusing on the histopathologic features and its implications in clinical practice.

Peribiliary Cysts Can Mimic Caroli’s Disease: A Case Report

Peribiliary cysts, otherwise known as cystic dilatation of the peribiliary glands, are uncommon, and are usually discovered incidentally at autopsy, or in explants following liver transplantation. Preoperative diagnosis is often difficult owing to their asymptomatic nature and small size. Exclusion of a premalignant or malignant cystic condition is mandatory. We report a case of peribiliary cysts, initially thought to represent Caroli’s disease, and briefly discuss the management of this condition.

Imaging of Von Meyenburg complexes

Von Meyenburg complexes, or biliary hamartomas, are frequently incidentally detected. They are usually easy to characterize with magnetic resonance imaging. However, in some occasions they are difficult to differentiate from other liver lesions, in particular from small liver metastases. Von Meyenburg complexes are developmental malformations of the ductal plate. They can be found in association with Caroli disease and Caroli syndrome. Like other ductal plate malformations, Von Meyenburg complexes associated with cholangiocarcinoma have been described and their relationship has been established. This review provides an update on the etiopathogenesis of Von Meyenburg complexes, illustrates the imaging features on ultrasound, CT and MRI of this condition and discusses the most common diagnostic pitfalls. The relationships between Von Meyenburg complexes and the various ductal plate malformations and the most recent literature data regarding the relationships between Von Meyenburg complexes and cholangiocarcinoma are presented.

Alcohol-related injury to peribiliary glands is a cause of peribiliary cysts: based on analysis of clinical and autopsy cases

BACKGROUND AND GOAL

Peribiliary cysts, which are known to be associated with various hepatobiliary diseases including alcoholic liver disease, have been reported to originate in the peribiliary glands along the biliary tree. The causal relationship between the peribiliary cysts and alcohol-related hepatic and pancreatic disease were examined in this study.

METHODS AND RESULTS

Peribiliary cysts were surveyed in the radiologic reports of out-patients and in-patients at our hospital (between 2007 and 2011), and a total of 31 patients with peribiliary cysts were found; 9 patients were associated with alcoholic liver disease and 2 patients with alcoholic pancreatitis. Among 202 consecutive autopsy cases with a history of heavy drinking (chronic alcoholics) at our Department (between 1990 and 2011), peribiliary cysts were found in 29 cases (14%), and the frequency of these cysts was correlated with the degree of alcohol-related hepatic fibrosis. Interestingly, peribiliary cysts were frequently associated with adenitis of the peribiliary glands (72%), and peribiliary adenitis and cyst formation correlated well with the degree of pancreatic fibrosis.

CONCLUSIONS

These results suggest that peribiliary cysts are more likely to occur in chronic alcoholics. The frequent association of peribiliary cysts with the degree of alcohol-related hepatic fibrosis suggests the involvement of the hepatic fibrogenetic process in peribiliary cyst formation. The frequent association of peribiliary adenitis and cyst formation with the degree of pancreatic fibrosis in chronic alcoholics suggests the involvement of alcoholic injuries in the pancreas, resulting in progressive fibrosis, and peribiliary glands, resulting in adenitis and cyst formation.

Peribiliary cysts developed in normal underlying liver: report of a case

Peribiliary cysts, known as cystic dilatation, of the extramural peribiliary glands of the bile duct are rare, and are usually detectable under conditions of pre-existing hepatobiliary diseases such as liver cirrhosis. Preoperative diagnosis is often difficult, because they are usually asymptomatic. Distinction of peribiliary cysts from premalignant or malignant cystic lesions is mandatory. Herein, we report a case of peribiliary cyst, which was preoperatively assumed as unilobar Caroli's diseases in healthy young patients and briefly discuss the management of the condition.

Role of follicle-stimulating hormone on biliary cyst growth in autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder characterized by the progressive development of renal and hepatic cysts. Follicle-stimulating hormone (FSH) has been demonstrated to be a trophic factor for biliary cells in normal rats and experimental cholestasis induced by bile duct ligation (BDL).

AIMS

To assess the effect of FSH on cholangiocyte proliferation during ADPKD using both in vivo and in vitro models.

METHODS

Evaluation of FSH receptor (FSHR), FSH, phospho-extracellular-regulated kinase (pERK) and c-myc expression in liver fragments from normal patients and patients with ADPKD. In vitro, we studied proliferating cell nuclear antigen (PCNA) and cAMP levels in a human immortalized, non-malignant cholangiocyte cell line (H69) and in an immortalized cell line obtained from the epithelium lining the hepatic cysts from the patients with ADPKD (LCDE) with or without transient silencing of the FSH gene.

RESULTS

Follicle-stimulating hormone is linked to the active proliferation of the cystic wall and to the localization of p-ERK and c-myc. This hormone sustains the biliary growth by activation of the cAMP/ERK signalling pathway.

CONCLUSION

These results showed that FSH has an important function in cystic growth acting on the cAMP pathway, demonstrating that it provides a target for medical therapy of hepatic cysts during ADPKD.

Immunohistochemical characteristics and malignant progression of hepatic cystic neoplasms in comparison with pancreatic counterparts

The recent World Health Organization classification for tumors of the digestive system defined grossly and histologically hepatic mucinous cystic neoplasms and intraductal papillary neoplasms of the bile duct separately. In this study, the immunohistochemical features of intraductal papillary neoplasm of the bile duct (19 cases) and hepatic mucinous cystic neoplasm (5 cases) were characterized and compared with those of similar pancreatic lesions, intraductal papillary mucinous neoplasm of the pancreas (12 cases), and pancreatic mucinous cystic neoplasm (6 cases) and with those of other biliary cystic lesions, peribiliary cysts (10 cases). Intraductal papillary neoplasm of the bile duct and intraductal papillary mucinous neoplasm of the pancreas frequently expressed cytokeratin 7; mucin core proteins 1, 2, 5AC, and 6; trypsin; and amylase. Hepatic and pancreatic mucinous cystic neoplasms frequently expressed cytokeratin 7, mucin core proteins 1 and 5AC, estrogen receptor, progesterone receptor, trypsin, and amylase. Estrogen and progesterone receptors were expressed in the subepithelial stromal cells. The groups with intraductal papillary neoplasm of the bile duct and intraductal papillary mucinous neoplasm of the pancreas were different from the groups with hepatic and pancreatic mucinous cystic neoplasm with respect to several phenotypes reflecting gastric and intestinal metaplasia and also the lack of expression of estrogen and progesterone receptors. The Ki-67 and p53 labeling indexes increased significantly with the malignant progression of intraductal papillary neoplasm of the bile duct and intraductal papillary mucinous neoplasm of the pancreas. The p16 labeling index decreased and EZH2 labeling index increased significantly with the malignant progression of intraductal papillary neoplasm of the bile duct and intraductal papillary mucinous neoplasm of the pancreas. In conclusion, intraductal papillary neoplasm of the bile duct and hepatic mucinous cystic neoplasm might be regarded as biliary counterparts of intraductal papillary mucinous neoplasm of the pancreas and pancreatic mucinous cystic neoplasm, respectively, and the mucinous cystic neoplasm and intraductal papillary neoplasm groups differed from each other. Labeling indexes of Ki-67, p53, p16, and EZH2 were comparable in intraductal papillary neoplasm of the bile duct and intraductal papillary mucinous neoplasm of the pancreas along with their malignant progression, suggesting a common carcinogenic process of the tumors.

Hepatic nodular hamartoma containing liver cysts, ductal plate malformations and peribiliary glands

An 83-year-old man with hepatocellular carcinoma was found to have a low-echoic and low-density tumor measuring 7.2 cm × 5.6 cm. Caroli's disease was absent. Clinical diagnosis was intrahepatic cholangiocarcinoma. Three cores of liver biopsy were obtained from the tumor. Histologically, it consisted of liver cysts, ductal plate malformations, peribiliary glands, hepatocytes, portal tracts and mesenchymal tissue. Apparent features of cirrhosis were not found. The liver cysts were lined by a layer of cuboidal cells with multiple papillary protrusions. The ductal plate malformations resembled fetal ductal plates. The peribiliary glands were seromucous glands. Immunohistochemically, these abnormal ductal structures showed positive reaction to biliary type cytokeratins, namely, cytokeratin (CK)7, CK8, CK18 and CK19. Mucin gene expression showed that these biliary structures are positive for fetal antigen MUC1. MUC6 is also positive in them. Aberrant expression of CD10 was observed in these biliary structures. MUC2, MUC5AC and CDX2 were negative. The author thinks that this lesion is hepatic hamartoma with ductal plate malformations, liver cysts and peribiliary glands. To the best of the author's knowledge, this type of liver nodule has not been reported in the published work.

[Intrahepatic biliary cystic lesions]

Intrahepatic biliary cysts encompass a large lesional spectrum including hereditary diseases as polycystic liver disease or Caroli's syndrome, malformative lesions as non hereditary Caroli's disease or simple biliary cyst and true neoplastic lesions as cystadenoma or cystadenocarcinoma. The diagnostic approach of these lesions relies firstly on imaging. Nevertheless, the pathologist not exceptionally receives surgical specimens from cystic fenestration or liver specimen resection with one or several cystic lesions. The clues for pathological diagnosis of these lesions have to be known by pathologists. As regards neoplastic cystic lesions, true non-communicating cystic tumors and cystic variants of intraductal biliary tumors have to be distinguished; in both cases, the classification is now identical to the one of pancreatic cystic tumors.

Monolobar ductal plate malformation disease of the liver

We herein report a unique monolobar hepatic disease composed of Caroli's disease, peribiliary cysts, ductal plate malformations, peribiliary gland proliferation, hepatolithiasis, and portal phlebosclerosis with thrombi. A 73-year-old man underwent abdominal imaging, which revealed multiple segmental dilations of the left intrahepatic bile ducts. Polycystic kidney diseases were absent. Intrahepatic cholangiocarcinoma was suspected, and extended left lobectomy of the liver was preformed. Grossly, the hepatic left lobe was atrophic, and partly replaced by fibrous tissue. The intrahepatic bile ducts were dilated (Caroli's disease), and showed small calcium bilirubinate hepatoliths. Microscopically, the intrahepatic bile duct showed non-obstructive segmental dilations (Caroli's disease), numerous peribiliary cysts, numerous ductal plate malformations, proliferation of intrahepatic peribiliary glands, and calcium bilirubinate hepatolithiasis. Portal veins showed phlebosclerosis with thrombi. Immunohistochemically, the various biliary epithelial cells were positive for cytokeratin (CK) 7, 8, 18, and 19, and for MUC6 and CD10. They were negative for MUC2 and MUC5AC. The ductal plate malformations were positive for fetal biliary antigen MUC1, but other biliary cell types were negative for MUC1. The present case resembles 'monolobar Caroli's disease'. We believe that the present monolobular liver disease was congenital in origin.

A novel approach to biliary tract pathology based on similarities to pancreatic counterparts: is the biliary tract an incomplete pancreas?

There are peribiliary glands around the biliary tract, and these glands drain into the bile duct lumen. Interestingly, small amounts of pancreatic exocrine acini are intermingled with these glands. Experimental studies using animals suggest that the biliary tract shows some potential for pancreatic differentiation. It is noteworth that the biliary tract and pancreas have similar pathological features. IgG4-related sclerosing cholangitis and autoimmune pancreatitis are representative inflammatory diseases with similar features. Intraductal papillary neoplasms are found in the biliary tract and also in the pancreas: intraductal papillary neoplasm of the bile duct (IPNB) and intraductal papillary mucinous neoplasm of the pancreas (IPMN). IPNB and IPMN share common histologic and phenotypic features and biological behaviors. Interestingly, mucinous cystic neoplasm (MCN) arises in both the pancreas and the hepatobiliary system. Intraductal tubular neoplasia is found in both the biliary tract and pancreas as well. Intraepithelial neoplasm is found in the biliary tract and pancreas: biliary intraepithelial neoplasm (BilIN) and pancreatic intraepithelial neoplasm (PanIN). BilIN and PanIN are followed by conventional invasive adenocarcinoma, while IPNB and IPMN are followed by tubular adenocarcinoma and mucinous carcinoma in both organs. Further study of the biliary tract's pathophysiology based on its similarity to pancreatic counterparts is warranted.

Monolobar hepatobiliary fibropolycystic disease

We herein report a case of monolobar hepatobiliary fibropolycystic disease. A 75-year-old woman presented with heartburn. Imaging modalities including US, CT, and MRI revealed marked atrophy and multiple biliary cysts of the hepatic left lobe. The hepatic right lobe was normal. ERCP and bile duct endoscopy revealed anomalous pancreaticobiliary union, choledochal dilation, dilation of left intrahepatic bile ducts, and small choledochal non-invasive adenocarcinoma. Polycystic kidney diseases were absent. The patient underwent pancreatico-duodenectomy and extended hepatic left lobectomy. Grossly, the hepatic left lobe was markedly atrophic, and studded with numerous biliary cysts. The left intrahepatic bile ducts were dilated (Caroli's disease) and the common bile duct showed type I choledochal dilation. The right hepatic lobe was normal. Histologically, the hepatic left lobe was replaced by fibroelastosis. The intrahepatic bile ducts showed ductal plate malformation such as irregular contours, invaginations, and protrusions. The numerous biliary cysts also showed ductal plate malformation. There were numerous persistent ductal plates and microhamartomas. Many hyalinized destructive biliary cysts and ductal plates were recognized. The liver parenchyma was scant and free of hepatocellular malformations. The portal veins showed old obliterative portal thrombosis. The right hepatic lobe was normal. Immunohistochemically, the biliary cells were positive for cytokeratin 7, 8, 18 and 19, and MUC6 and CD10, but negative for MUC2 and MUC5AC. The biliary cysts, persistent ductal plate, and microhamartomas were positive for fetal apomucin antigen MUC1.

Congenital disorders of glycosylation in hepatology: the example of polycystic liver disease

Autosomal dominant polycystic liver disease (PCLD) is a rare progressive disorder characterized by an increased liver volume due to many (>20) fluid-filled cysts of biliary origin. Disease causing mutations in PRKCSH or SEC63 are found in approximately 25% of the PCLD patients. Both gene products function in the endoplasmic reticulum, however, the molecular mechanism behind cyst formation remains to be elucidated. As part of the translocon complex, SEC63 plays a role in protein import into the ER and is implicated in the export of unfolded proteins to the cytoplasm during ER-associated degradation (ERAD). PRKCSH codes for the beta-subunit of glucosidase II (hepatocystin), which cleaves two glucose residues of Glc(3)Man(9)GlcNAc(2) N-glycans on proteins. Hepatocystin is thereby directly involved in the protein folding process by regulating protein binding to calnexin/calreticulin in the ER. A separate group of genetic diseases affecting protein N-glycosylation in the ER is formed by the congenital disorders of glycosylation (CDG). In distinct subtypes of this autosomal recessive multisystem disease specific liver symptoms have been reported that overlap with PCLD. Recent research revealed novel insights in PCLD disease pathology such as the absence of hepatocystin from cyst epithelia indicating a two-hit model for PCLD cystogenesis. This opens the way to speculate about a recessive mechanism for PCLD pathophysiology and shared molecular pathways between CDG and PCLD. In this review we will discuss the clinical-genetic features of PCLD and CDG as well as their biochemical pathways with the aim to identify novel directions of research into cystogenesis.

Surgical management of polycystic liver disease

Adult polycystic liver disease (PCLD) is an autosomal dominant condition commonly associated with autosomal dominant polycystic kidney disease (ADPKD). However in the last decade, it has been recognized that there is a distinct form of autosomal dominant PCLD that arises without concomitant ADPKD. Early knowledge of the pathogenesis was gained from the study of hepatic cysts in patients with ADPKD. Bile duct overgrowth after embryogenesis results in cystic hepatic dilatations that are known as biliary microhamartomas or von Meyenburg complexes. Further dilatation arises from cellular proliferation and fluid secretion into these cysts. There is a variable, broad spectrum of manifestations of PCLD. Although PCLD is most often asymptomatic, massive hepatomegaly can lead to disabling symptoms of abdominal pain, early satiety, persistent nausea, dyspnea, ascites, biliary obstruction, and lower body edema. Complications of PCLD include cyst rupture and cyst infection. Also, there are associated medical problems, especially intracranial aneurysms and valvular heart disease, which clinicians need to be aware of and evaluate in patients with PCLD. In asymptomatic patients, no treatment is indicated for PCLD. In the symptomatic patient, surgical therapy is the mainstay of treatment tailored to the extent of disease for each patient. Management options include cyst aspiration and sclerosis, open or laparoscopic fenestration, liver resection with fenestration, and liver transplantation. The surgical literature discussing treatment of PCLD, including techniques, outcomes, and complication rates, are summarized in this review.

Multiple hepatic peribiliary cysts in a young pig

Histopathologic features of hepatic peribiliary cysts were described in a young slaughtered pig. The animal was an apparently healthy 6-month-old pig of mixed breed. Macroscopically, all lobes of the liver contained numerous cysts of varying size containing serous fluid in all lobes. Histopathologically, the cysts were located mainly around the large bile duct and in the connective tissue of the portal tracts. Within serial sections, these cysts were assumed to be solitary or multilocular, but they were separated from the bile duct. The cysts were lined by a single layer of columnar, cuboidal, and flattened epithelial cells. Occasionally, goblet cells were observed. The epithelial cells were stained with periodic acid-Schiff/alcian blue and high-iron diamine/alcian blue, indicating the presence of neutral mucin, sialomucin, and sulfomucin. Grimalius' method revealed the presence of endocrine cells in the lining epithelium. There was no bile pigment in the cysts by the Hall method.

An autopsy case of obstructive jaundice due to hepatic multiple peribiliary cysts accompanying hepatolithiasis

A 73-year-old Japanese male, who had a history of alcoholic cirrhosis, was admitted to Saga University Hospital to receive treatment for hepatocellular carcinoma. The patient was treated to maintain his liver function, however, the total bilirubin level continued to increase gradually. Endoscopic retrograde cholangiography demonstrated an obstruction of the bilateral intrahepatic ducts. Although endoscopic nasobiliary drainage was performed, the patient died two months after admission. At the autopsy, multiple peribiliary cysts were found to almost completely obstruct the bilateral intrahepatic bile ducts. In addition, hepatolithiasis was found in the right hepatic duct. To date, only a few such cases of multipleperibiliary cysts with obstructive jaundice have been reported, and no such case accompanied by hepatolithiasis. It is also important to note that all the reported cases resulted in a poor prognosis. We herein report a very rare autopsy case with obstructive jaundice due to multiple peribiliary cysts accompanying hepatolithiasis. Generally, multiple peribiliary cysts are considered to be clinically harmless, but once they cause obstructive jaundice, their presence suggests the occurrence of end-stage cirrhosis and a poor prognosis.

Expression profiles of MUC mucins and trefoil factor family (TFF) peptides in the intrahepatic biliary system: physiological distribution and pathological significance

Mucin secreted by mucosal epithelial cells plays a role in the protection of the mucosal surface and also is involved in pathological processes. So far, MUC1-4, 5AC, 5B, 6-8, 11-13 and 15-17 genes coding the backbone mucin core protein have been identified in humans. Their diverse physiological distribution and pathological alterations have been reported. Trefoil factor family (TFF) peptides are mucin-associated molecules co-expressed with MUC mucins and involved in the maintenance of mucosal barrier and the biological behavior of epithelial and carcinoma cells. Intrahepatic biliary system is a route linking the bile canaliculi and the extrahepatic bile duct for the excretion of bile synthesized by hepatocytes. Biliary epithelial cells line in the intrahepatic biliary system, secreting mucin and other molecules involved in the maintenance and regulation of the system. In this review, the latest information regarding properties, expression profiles and regulation of MUC mucins and TFF peptides in the intrahepatic biliary system is summarized. In particular, we focus on the expression profiles and their significance of MUC mucins in developmental and normal livers, various hepatobiliary diseases and intrahepatic cholangiocarcinoma.

Solitary liver cysts in children: not always so simple

AIM

Liver cysts in children are uncommon. Many are simple and solitary and do not require intervention. However, this series demonstrates a broad range of potential pathologies, some of which are life-threatening.

METHODS

All children referred to our unit during an 8-year period (1998-2005) and found to have a solitary liver cyst were prospectively recorded. Clinical, radiologic, and pathologic features were analyzed. Children with an isolated extrahepatic choledochal cyst and polycystic disease were excluded.

RESULTS

Twenty-one children with a liver cyst were identified. Two had undergone unsuccessful surgical intervention before referral. There were 11 prenatally detected cysts. Median gestational age at detection was 22 weeks (19-35 weeks); only 1 was specifically characterized as a liver cyst prenatally. Six of these required surgery: 2 large simple cysts, 2 intrahepatic choledochal cysts, 1 giant complex biliary cyst causing respiratory distress, and 1 ciliated hepatic foregut cyst. Of the 5 cysts remaining under ultrasound surveillance, 4 decreased in size or resolved. In 10 children presenting between birth and 15.8 years, a liver cyst was diagnosed postnatally: 3 huge cystic mesenchymal hamartomas, 1 type V choledochal cyst, 1 hydatid cyst, and 5 simple cysts. Four of these required surgical resection. Simple cysts tended to be small and could be distinguished from other pathologies using a combination of imaging techniques (ultrasound, magnetic resonance imaging/magnetic resonance cholangiopancreatography [MRCP], radionuclide scan). Only 2 of 12 children with "simple" cysts required surgery for symptoms. However, a wide range of other cyst pathologies were found in 9 children, and although none was malignant, some were life-threatening and 7 required resection.

CONCLUSIONS

Simple solitary nonparasitic liver cysts rarely cause symptoms or require surgery, but the pediatric surgeon should be aware of the wide range of other types of liver cyst in children to ensure appropriate treatment.

The hepatic fibrocystic diseases

The hepatic fibrocystic diseases present with variable intrahepatic biliary abnormalities, which range from portal tract enlargement and fibrosis to cystic formations. They may present as autosomal recessive or dominant polycystic kidney diseases, with associated dilatation of the renal collecting system, or as incompletely characterized cystic diseases. Symptoms from the liver disease often result from complications of fibrosis or dilated ducts/cyst (sludge, lithiasis, infection). The treatment is supportive, with careful attention to associated renal disease. Liver transplantation is an option in selected patients.

Secretion and expression of epithelial markers supports the biliary origin of solitary nonparasitic cyst of the liver in infancy

Solitary nonparasitic cyst of the liver (SNPCL) is rare in children. Although there are several hypotheses regarding the pathogenesis, the true origin of SNPCL remains unknown. The authors present an infant with a huge SNPCL in whom the epithelial markers, CA19-9, DU-PAN-2, and SPan-1, were elevated in the serum and cystic fluid. The presence of CA19-9 and DU-PAN-2 was shown by immunohistochemistry in the cystic epithelia. These indicate that the classical idea of biliary origin of SNPCL is supported.

Solitary bile duct hamartoma of the liver

Bile duct hamartomas, also known as von Meyenburg complexes, are benign liver malformations which usually present as multiple small nodules scattered in both lobes of the liver. We report a unique case of bile duct hamartoma. An asymptomatic 30-year-old man who had a solitary cystic lesion underwent partial hepatectomy. Macroscopically, the lesion, measuring 3.6 cm in diameter, was composed of a number of small grayish-white cysts measuring 0.1 to 1.2 cm in diameter. Histologically, the constituent cysts were embedded in a fibrous stroma and were lined by low columnar or cuboidal epithelium. By immunohistochemistry, the MIB-1 index was below 1%, and p53 and carcinoembryonic antigen (CEA) were negative. These findings lead us to conjecture that the lesion was a bile duct hamartoma, although its solitary nature and large size differed from those of typical bile duct hamartoma.

Polycystic liver and kidney diseases

There have been remarkable advances in research on polycystic liver and kidney diseases recently, covering cloning of new genes, refining disease classifications, and advances in understanding more about the molecular pathology of these diseases. Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary disease affecting kidneys. It affects 1/400 to 1/1000 live births and accounts for 5% of the end stage renal disease in the United States and Europe, and is caused by gene defects in the PKD1 or PKD2 genes. Compared to ADPKD, polycystic liver disease (PCLD) is a milder disease and does not lower life expectancy. Both diseases are usually adult-onset diseases. Defects in genes, which code the hepatocystin and SEC63 proteins, have just recently been found to cause PCLD. It now seems that ADPKD is caused by malfunction of the primary cilia, a cell organ sensing fluid movement, and that PCLD is a sequel from defects in protein processing. Autosomal recessive polycystic kidney disease (ARPKD) belongs to a group of congenital hepatorenal fibrocystic syndromes. All ARPKD patients have a gene defect in a gene called PKHD1, the protein product of which localizes to primary cilia. We summarize the present clinical and molecular knowledge of these diseases in this review.

Cholesterol hepatolithiasis with peribiliary cysts

A 78-year-old man was admitted to our clinic because of fatigue. Imaging modalities showed beaded stricture and dilation of the intrahepatic left segmental bile duct. Anomalous pancreatico-biliary ductal union and polycystic kidney disease were absent. Resection of the hepatic left lobe was performed. Grossly, cholesterol stones were impacted in the dilated intrahepatic large bile ducts, and multiple tiny cysts measuring 2-8 mm were noted in the peribiliary areas (peribiliary cysts). Histologically, the cholesterol hepatoliths consisted of cholesterol empty spaces and fibrinous materials, and, in places, foreign body giant cells were seen around the cholesterol crystals. The peribiliary cysts were lined by a layer of cuboidal epithelia. They were intimately intermingled with intrahepatic peribiliary glands, and a close association between the two components was recognized in some places. A mild degree of ascending cholangitis was noted. Bile duct anomalies including von-Meyenburg complexes and simple cysts were not recognized. Peribiliary cysts have been reported in various liver diseases, including portal hypertension, portal thrombosis, cirrhosis, hepatocellular carcinoma, and adult polycystic kidney disease. However, to the best of our knowledge, there have been no reports on peribiliary cysts developing in hepatolithiasis. The present case indicates that peribiliary cysts occur in cholesterol hepatolithiasis, and suggests that they are derived from cystic dilations of intrahepatic peribiliary glands.

Unusual hepatic tumor with features of mesenchymal hamartoma and congenital solitary nonparasitic cyst

We report a hepatic tumor in an adolescent that does not fit into any of the described categories of liver tumors. The patient presented with hepatomegaly, abdominal pain, and normal liver function test; the tumor was cystic in imaging studies. The resected specimen, result of a partial hepatectomy, measured 21 cm and was multicystic with solid areas. Microscopically, the cysts were lined by a mucous-producing or intestinal-type epithelium, associated with smooth muscle and small mucous-producing glands. The solid component contained fibrous and adipose tissue, smooth muscle and thick-walled vessels. Aneuploidy was demonstrated by flow cytometry. We interpreted the tumor as having features of a mesenchymal hamartoma and congenital solitary nonparasitic cyst. It is conceivable that the lesions originated with small peribiliary glands with dilatation and intestinal metaplasia.

Mutations in PRKCSH cause isolated autosomal dominant polycystic liver disease

Autosomal dominant polycystic liver disease (ADPLD) is a distinct clinical and genetic entity that can occur independently from autosomal dominant polycystic kidney disease (ADPKD). We previously studied two large kindreds and reported localization of a gene for ADPLD to an approximately 8-Mb region, flanked by markers D19S586/D19S583 and D19S593/D19S579, on chromosome 19p13.2-13.1. Expansion of these kindreds and identification of an additional family allowed us to define flanking markers CA267 and CA048 in an approximately 3-Mb region containing >70 candidate genes. We used a combination of denaturing high-performance liquid chromatography (DHPLC) heteroduplex analysis and direct sequencing to screen a panel of 15 unrelated affected individuals for mutations in genes from this interval. We found sequence variations in a known gene, PRKCSH, that were not observed in control individuals, that segregated with the disease haplotype, and that were predicted to be chain-terminating mutations. In contrast to PKD1, PKD2, and PKHD1, PRKCSH encodes a previously described human protein termed "protein kinase C substrate 80K-H" or "noncatalytic beta-subunit of glucosidase II." This protein is highly conserved, is expressed in all tissues tested, and contains a leader sequence, an LDLa domain, two EF-hand domains, and a conserved C-terminal HDEL sequence. Its function may be dependent on calcium binding, and its putative actions include the regulation of N-glycosylation of proteins and signal transduction via fibroblast growth-factor receptor. In light of the focal nature of liver cysts in ADPLD, the apparent loss-of-function mutations in PRKCSH, and the two-hit mechanism operational in dominant polycystic kidney disease, ADPLD may also occur by a two-hit mechanism.

Clinical profile of autosomal dominant polycystic liver disease

Most reports on the natural history, manifestations, and treatment of polycystic liver disease are based on the disease as it manifests in patients with autosomal dominant polycystic kidney disease (ADPKD). The purpose of this study was to develop a clinical profile of isolated autosomal dominant polycystic liver disease (ADPLD) using nonaffected family members as controls. The study included 146 probands, known affected relatives, and first-degree relatives of affected individuals. Participants underwent a formalized medical history interview and physical examination, ultrasonographic examination of the liver and kidneys, magnetic resonance angiography of the brain, and echocardiography. Thirty-eight of the 49 individuals diagnosed with polycystic liver disease before participation in the study were or had been symptomatic. Of 97 previously undiagnosed at-risk individuals, 23 were affected, 39 were unaffected, and 35 were indeterminate. Compared with patients with a negative or indeterminate diagnosis, those with polycystic liver disease had slightly higher levels of serum alkaline phosphatase and total bilirubin and lower levels of total cholesterol and triglycerides. Female patients had a significantly higher mean cyst score than male patients. The cysts were found to arise from the dilatation of biliary microhamartomas and from peribiliary glands. Structural mitral leaflet abnormalities were detected more frequently in affected than in indeterminate or nonaffected individuals. A vascular phenotype was detected in 5.6% of the patients with isolated ADPLD diagnosed clinically and/or by linkage analysis but in none of the unaffected patients. In conclusion, isolated ADPLD is underdiagnosed and genetically distinct from polycystic liver disease associated with ADPKD but with similar pathogenesis, manifestations, and management.

Small hypoattenuating lesions in the liver on single-phase helical CT in preoperative patients with gastric and colorectal cancer: prevalence, significance, and differentiating features

PURPOSE

The purpose of this study was to determine the prevalence and significance of small low attenuating hepatic lesions (SLAHs) seen on helical CT in preoperative patients with gastric and colorectal cancers and to find differentiating features of benign from malignant SLAH.

SUBJECTS AND METHODS

By the retrospective review of preoperative helical CT scans in 1,133 consecutive patients with proved gastric and colorectal cancers, 289 patients (25.5%) with 947 SLAHs (</=15 mm) were selected. Among them, 66 SLAHs in 21 patients without final diagnosis were excluded. The size, margin, shape, attenuation, and enhancement features of the lesions were evaluated. For 200 randomly selected SLAHs, interobserver agreement for each parameter was assessed.

RESULTS

Among 881 SLAHs in 268 patients, 693 (78.3%) in 248 patients (92.5%) were benign, and 188 (21.2%) in 30 patients (11.2%) were metastases; 10 patients (3.7%) had both. Among SLAHs in patients who had SLAHs only, 14 lesions (1.6%) in 6 patients (2.2%) were metastases. Benign SLAHs were smaller (6.4 +/- 3.1 mm; P < 0.001) and more frequently had discrete margin (P < 0.001) and markedly low attenuation (P < 0.001) than metastases (9.3 +/- 2.7 mm). Target-enhancement was far more frequent in metastases (64.4%) than benign SLAHs (1.2%; P < 0.001). Excellent interobserver agreement (kappa > 0.60) was found for all parameters in SLAHs larger than 5 mm.

CONCLUSION

The prevalence (25.5%) of SLAH on helical CT was higher than that reported on conventional CT; however, metastases only presenting as SLAH were rare (2.2%). For SLAHs larger than 5 mm, careful analysis of CT findings can be helpful to differentiate benign from malignant SLAH.

MRI for evaluating congenital bile duct abnormalities

Congenital bile duct diseases consist of ductal plate development abnormalities and are genetically determined. These biliary abnormalities are encountered mainly in congenital fibrocystic diseases, represented by congenital hepatic fibrosis and different forms of Caroli disease. On the other hand, polycystic hepatic diseases also present cystic abnormalities, which could be confused with biliary dilatations, especially in the perihilar area. Further, intricate forms between Caroli and polycystic hepatic diseases are possible. In congenital bile duct paucity, which is extremely rare, the biliary tree, located on the opposite, is not visible. MRI modalities for the analysis of the biliary tree are mainly represented by T -weighted sequence, also known as MR cholangiography (MRCP), and T gadolinium-enhanced sequences. Familiarity with the most common appearances of congenital bile duct dilations, its variants, and related complex diseases facilitates accurate diagnosis and allows and helps avoid misinterpretation.

MR cholangiography in the evaluation of hepatic and biliary abnormalities in autosomal dominant polycystic kidney disease: study of 93 patients

PURPOSE

The purpose of this work was to conduct an MR cholangiography study of hepatobiliary abnormalities in autosomal dominant polycystic kidney disease (ADPKD) and to correlate these abnormalities with the risk of infection.

METHOD

Cystic and intrahepatic bile duct (IHBD) abnormalities identified by MR cholangiography in 93 ADPKD patients were studied retrospectively. A blind study of liver function tests, renal insufficiency, and infectious episodes was also carried out. Correlations among these data were looked for using univariate analysis.

RESULTS

Intrahepatic cysts were present in 84 of 93 patients and peribiliary cysts in 59 of 90 patients. IHBDs were abnormal in 25 of 90 patients (tubular dilatation in 15 cases and bead-like dilatation in 16). IHBD abnormalities were correlated with hepatobiliary infections (p = 0.0012), gamma-glutamyltranspeptidase elevation (p = 0.018), and terminal renal failure (p = 0.006).

CONCLUSION

This study confirms the complexity of hepatobiliary involvement in ADPKD. Various types of cystic lesions can arise, and patients with IHBD abnormalities are at increased risk for hepatobiliary infection.

Multiple hepatic peribiliary cysts discovered incidentally at a medical examination

We report a living patient with multiple hepatic peribiliary cysts. It was discovered incidentally during an ultrasonographic screening at a medical examination. Peribiliary cysts are multiple retention cysts of peribiliary glands. Although many autopsy cases of peribiliary cysts have been reported, there are few clinical cases of it in living patients. A CT performed immediately after drip-infusion cholangiography (DIC) was most useful for diagnosis in various imaging tests we performed.

Spontaneous disappearance of a hepatic cyst

The spontaneous disappearance of a hepatic cyst is described. A 62-year-old woman presented with symptoms of general fatigue in August 1992. Her past medical history was significant for chronic hepatitis, which was diagnosed in 1990 but not treated. Initial laboratory tests revealed mild liver dysfunction with a positive serologic test for hepatitis C. In August 1992, ultrasonography and computed tomography disclosed a cystic lesion along the middle hepatic vein in the right anterior segment of the liver, which was 40 mm in diameter. Repeat radiologic studies in June 1994 demonstrated that the size of the cyst was unchanged. In May 1995, the cyst was only 25 mm in diameter, and it continued to decrease in size thereafter, to 10 mm in September 1995 and 7 mm in September 1996. No hepatic cyst was visualized in December 1996, though the region in which the cyst existed was hyperechoic. Laboratory data were essentially unchanged from August 1992 to December 1996. Clinically the patient remained asymptomatic.

Prevalence and importance of small hepatic lesions found at CT in patients with cancer

PURPOSE

To assess the prevalence of small hepatic lesions discovered at computed tomography (CT) in patients with cancer and to determine the frequency with which they represent clinically important findings.

MATERIALS AND METHODS

The authors reviewed the CT reports obtained in 2,978 patients with cancer during a 24-month period. Small hepatic lesions (lesions 1 cm or less in diameter or deemed too small to characterize by the interpreting radiologist) noted on the initial scan were assessed at follow-up CT. The number and type of any other intrahepatic lesion, the histologic type of the primary tumor, and the presence of extrahepatic metastatic disease were also recorded.

RESULTS

Small hepatic lesions were reported in 378 (12.7%) patients; 15 (4.0%) of these patients also reportedly had other larger hepatic lesions that were interpreted as metastases. Small hepatic lesions demonstrated interval growth in 44 (11.6%) patients and were therefore considered metastatic. Small hepatic lesions in 303 (80.2%) patients demonstrated no interval growth (mean follow-up, 25.6 months; range, 6-56 months) and were therefore presumed benign. Small hepatic lesions in 31 (8.2%) patients were stable at follow-up of less than 6 months and were considered indeterminate. Among the three most common tumors (lymphoma and colorectal and breast cancers), small hepatic lesions were metastatic in 4%, 14%, and 22%, respectively.

CONCLUSION

Although small hepatic lesions in patients with cancer more frequently are benign than malignant, these lesions represent metastases in 11.6% of patients.

Von Meyenburg complexes of the liver: imaging findings

PURPOSE

Our purpose was to present imaging findings of six cases proven or supposed to be von Meyenburg complexes (VMCs) with a basis of reviewing the pathologic literature and to describe imaging points for the diagnosis of typical VMC along with its differential diagnosis.

METHOD

Six cases were diagnosed as VMC of the liver with imaging modalities (one had histopathologic proof). Both ultrasound (US) and CT were available for all cases, and MRI was used for three cases. Follow-up with US, CT and/or MRI was performed in five cases.

RESULTS

US detected varying abnormalities of the livers in four cases. CT and MRI revealed multiple or numerous intrahepatic tiny (usually < 5 mm) cystoid lesions in all of the cases. The lesions were scattered throughout the livers, and some of them were located more frequently adjacent to the medium-sized portal veins than to the hepatic veins of similar size on CT. Moreover, some lesions were apparently located in the subcapsular areas (up to the hepatic capsules). They were usually irregular in shape and showed no enhancement but increased in number by approximately 80-150% after administration of intravenous contrast medium. The T2-weighted MR images and MR cholangiopancreatography showed the lesions to be much more apparent and to be more numerous than T1-weighted images did. Follow-up of five cases with imaging modalities did not show remarkable change of the lesions.

CONCLUSION

Despite our limited experience, VMC lesions seem to show some CT and MR features different from those of other multiple small hepatic lesions. They presented as multiple or numerous intrahepatic tiny cystoid lesions usually with irregular contour, scattered throughout the liver up to the subcapsular areas, and were detected in far greater number by enhanced CT or T2-weighted MR images than by unenhanced CT or T1-weighted images. They showed no remarkable change on long term follow-up imaging. We propose that a diagnosis of typical VMC could be made after analyzing CT or MR images carefully with good understanding of its pathologic basis, but imaging follow-up is necessary in oncology patients.

Ludwig symposium on biliary disorders--part I. Pathogenesis of ductal plate abnormalities

Intrahepatic bile ducts (IHBDs) develop from bipotential liver progenitor cells in contact with the mesenchyme of the portal vein and thus form the "ductal plates." The ductal plates are remodeled into mature tubular ducts. Lack of remodeling results in the persistence of periportal epithelial sleeves or "ductal plate malformation" (DPM). A proposal is that virtually all congenital diseases of IHBDs represent examples of DPM. Some early, severe types of extrahepatic bile duct atresia are characterized by DPM, a suggestion of a prenatal beginning of the disease. Several congenital diseases are characterized by dilatation of segments of IHBDs and variable degrees of fibrosis. Such "fibrocystic diseases" represent DPM at different levels of the biliary tree. Autosomal recessive polycystic kidney disease represents DPM of interlobular bile ducts, associated with tubular dilatation of collecting renal tubules. Congenital hepatic fibrosis may derive from the same type of liver lesion, through a superimposed destructive type of cholangiopathy associated with scarring fibrosis. Caroli's disease represents DPM of the larger IHBDs, whereas Caroli's syndrome combines the lesions of Caroli's disease and congenital hepatic fibrosis. von Meyenburg complexes represent DPM of smaller interlobular ducts; their dilatation gives rise to the liver cysts in autosomal dominant polycystic kidney disease. Finally, DPM is a component of the tissue abnormalities in so-called mesenchymal hamartoma.

Magnetic resonance imaging of focal and diffuse hepatic disease

MRI is a powerful tool in the detection and characterization of both focal and diffuse liver pathology. Because of superior soft tissue characterization, direct multi-planar capabilities and lack of ionizing radiation, current state of the art MRI is useful when contrast CT is relatively contraindicated or not definitive. This article reviews the MRI findings of the most common focal and diffuse liver diseases encountered in clinical practice. Reviews of current MR techniques and MR contrast agents used in liver imaging have been recently published. For this article, discussion of specific techniques and use of contrast is addressed for each pathological entity discussed.