Congenital Cystic Lesions of the Bile Ducts: Imaging-Based Diagnosis

Imaging of Biliary Tree Abnormalities

Pathologic conditions of the biliary system, although common, can be difficult to diagnose clinically. Challenges in biliary imaging include anatomic variants and the dynamic nature of the biliary tract, which can change with age and intervention, blurring the boundaries of normal and abnormal. Choledochal cysts can have numerous appearances and are important to diagnose given the risk of cholangiocarcinoma potentially requiring surgical resection. Choledocholithiasis, the most common cause of biliary dilatation, can be difficult to detect at US and CT, with MRI having the highest sensitivity. However, knowledge of the imaging pitfalls of MRI and MR cholangiopancreatography is crucial to avoid misinterpretation. Newer concepts in biliary tract malignancy include intraductal papillary biliary neoplasms that may develop into cholangiocarcinoma. New paradigms in the classification of cholangiocarcinoma correspond to the wide range of imaging appearances of the disease and have implications for prognosis. Accurately staging cholangiocarcinoma is imperative, given expanding curative options including transplant and more aggressive surgical options. Infections of the biliary tree include acute cholangitis or recurrent pyogenic cholangitis, characterized by obstruction, strictures, and central biliary dilatation. Inflammatory conditions include primary sclerosing cholangitis, which features strictures and fibrosis but can be difficult to differentiate from secondary causes of sclerosing cholangitis, including more recently described entities such as immunoglobulin G4-related sclerosing cholangitis and COVID-19 secondary sclerosing cholangitis. The authors describe a wide variety of benign and malignant biliary tract abnormalities, highlight differentiating features of the cholangitides, provide an approach to interpretation based on the pattern of imaging findings, and discuss pearls and pitfalls of imaging to facilitate accurate diagnosis. ©RSNA, 2024 Supplemental material is available for this article.

Caroli's disease misdiagnosed as bile duct cystadenoma: A case report

Caroli's disease is also known as Congenital intrahepatic bile duct dilatation, and previously known as a congenital intrahepatic bile duct cyst; it is characterized by single or multiple intrahepatic cystic dilatations. In this article, we report a case of Caroli's disease (CT size 21.2 × 16.9 × 19.8 cm). Preoperative abdominal ultrasound and enhanced CT were misdiagnosed as biliary cystadenoma or hepatic echinococcosis, and finally diagnosed as Caroli's disease by postoperative histopathological examinations. Most of the disease is single or multiple cystic dilatation of small bile duct. Giant Caroli disease, cystic dilations with diameter >20 cm is very rarely seen in the clinic. The lack of experience of diagnosing giant cystic dilatation makes it difficult to make accurate diagnosis. Therefore, we analyze the causes of imaging misdiagnosis through this case report, and summarize the imaging diagnostic skills of the disease combined with relevant imaging diagnosis experience. The purpose of this study is to deepen the understanding of giant Caroli disease among imaging doctors so as to reduce the misdiagnosis of the disease in the future.

Pediatric Hepatic Cystic Lesions: Differential Diagnosis and Multimodality Imaging Approach

When a pediatric hepatic cystic lesion is identified at imaging, the differential diagnosis may be broad, including developmental, infectious, neoplastic, and posttraumatic or iatrogenic causes. The location of a cystic lesion and its number, size, composition, and relationship to the biliary system are features that help in narrowing the differential diagnosis. An incidentally detected simple hepatic cyst is the most commonly encountered. Ciliated foregut cysts are typically located in hepatic segment IVa. The presence of multiple cysts should raise suspicion for fibropolycystic liver disease, a group of related lesions-including biliary hamartoma and choledochal cyst-caused by abnormal embryologic development of the ductal plate. Communication of the cystic lesion with the biliary tree can confirm the diagnosis of choledochal cyst. In a neonate with jaundice, a cystic lesion at the porta hepatis should raise suspicion for choledochal cyst versus cystic biliary atresia. Hepatic abscess can appear cystlike, though typically with internal contents. In an immunocompromised child, multiple cystlike lesions should raise concern for fungal microabscesses. A complex cystic mass in a young child should raise suspicion for mesenchymal hamartoma, which can evolve into undifferentiated embryonal sarcoma if untreated. Hepatic hematoma and biloma can appear cystlike in children with a history of trauma or recent intervention. In neonates with an umbilical vein catheter (UVC), an intrahepatic cyst along the course of the UVC should raise concern for infusate extravasation. Familiarity with imaging findings and clinical features is essential for achieving accurate diagnosis of pediatric hepatic cystic lesions, which in turn can guide appropriate clinical management. Online supplemental material is available for this article. ^©RSNA, 2022.

Imaging of fibropolycystic liver disease

Fibropolycystic liver diseases (FLDs) make up a rare spectrum of heritable hepatobiliary diseases resulting from congenital ductal plate malformations (DPMs) due to the dysfunction of proteins expressed on the primary cilia of cholangiocytes. The embryonic development of the ductal plate is key to understanding this spectrum of diseases. In particular, DPMs can result in various degrees of intrahepatic duct involvement and a wide spectrum of cholangiopathies, including congenital hepatic fibrosis, Caroli disease, polycystic liver disease, and Von Meyenberg complexes. The most common clinical manifestations of FLDs are portal hypertension, cholestasis, cholangitis, and (in rare cases) cholangiocarcinoma. This article reviews recent updates in the pathophysiology, imaging, and clinical management of FLDs.

Fibrocystic liver disease: novel concepts and translational perspectives

Fibrocystic liver diseases (FLDs) comprise a heterogeneous group of rare diseases of the biliary tree, having in common an abnormal development of the embryonic ductal plate caused by genetically-determined dysfunctions of proteins expressed in the primary cilia of cholangiocytes (and therefore grouped among the "ciliopathies"). The ductal dysgenesis may affect the biliary system at multiple levels, from the small intrahepatic bile ducts [congenital hepatic fibrosis (CHF)], to the larger intrahepatic bile ducts [Caroli disease (CD), or Caroli syndrome (CS), when CD coexists with CHF], leading to biliary microhamartomas and segmental bile duct dilations. Biliary changes are accompanied by progressive deposition of abundant peribiliary fibrosis. Peribiliary fibrosis and biliary cysts are the fundamental lesions of FLDs and are responsible for the main clinical manifestations, such as portal hypertension, recurrent cholangitis, cholestasis, sepsis and eventually cholangiocarcinoma. Furthermore, FLDs often associate with a spectrum of disorders affecting primarily the kidney. Among them, the autosomal recessive polycystic kidney disease (ARPKD) is the most frequent, and the renal function impairment is central in disease progression. CHF, CD/CS, and ARPKD are caused by a number of mutations in polycystic kidney hepatic disease 1 (PKHD1), a gene that encodes for fibrocystin/polyductin, a protein of unclear function, but supposedly involved in planar cell polarity and other fundamental cell functions. Targeted medical therapy is not available yet and thus the current treatment aims at controlling the complications. Interventional radiology or surgical treatments, including liver transplantation, are used in selected cases.

Factors contributing to diagnostic delay of Caroli syndrome: a single-center, retrospective study

Background

Caroli syndrome (CS) is a rare congenital disorder without pathognomonic clinical symptoms or laboratory findings; therefore, the diagnosis is often delayed. The objective of this study was to investigate the diagnostic delay and associated risk factors in CS patients.

Methods

This was a retrospective analysis of 16 CS patients admitted to a single tertiary medical center on mainland China. The diagnostic timelines of CS patients were reviewed to demonstrate the initial findings of CS at diagnosis, the risk factors associated with diagnostic delay, and potential clues leading to early diagnosis.

Results

The median diagnostic delay was 1.75 years (range: 1 month to 29 years, interquartile range: 6.2 years) in 16 enrolled CS patients. Sex, age, and initial symptoms were not associated with diagnostic delay. 87.5% of CS patients were diagnosed by imaging, and the accuracies of ultrasonography, computed tomography (CT), and magnetic resonance cholangiopancreatography were 25, 69.2, and 83.3%, respectively. The median diagnostic delays for patients with or without CT performed at the first hospital visited according to physician and radiologist suspicion of the diagnosis were 7.4 months and 6 years, respectively (p = 0.021). Hepatic cysts with splenomegaly were detected by ultrasound in over half of CS patients.

Conclusions

The majority of CS patients were not diagnosed until complications of portal hypertension had already developed. Recognition and early suspicion of the disease were important factors influencing diagnostic delay of CS. Hepatic cysts plus splenomegaly detected by US might raise the clinical suspicion to include CS in the differential diagnosis.

Hilar Fibropolycystic Liver Disease of Unknown Etiology: A Revelation from the Explant Liver

Fibropolycystic diseases of the liver comprise a spectrum of disorders affecting bile ducts of various sizes and arise due to an underlying ductal plate malformation (DPM). We encountered a previously unreported variant of DPM, the hilar fibropolycystic disease which we diagnosed in the explant liver. A 2-year-old boy was referred for liver transplantation with a diagnosis of biliary atresia (BA) and failed Kasai portoenterostomy (KPE). He had cirrhosis with portal hypertension along with synthetic failure indicated by coagulopathy and hypoalbuminemia. The child underwent liver transplant successfully. The explant liver had fibropolycystic disease confined to the perihilar liver and hilum. No pathogenic mutation was detected by whole exome sequencing. Fibropolycystic liver disease may represent a peculiar anatomical variant, which can be diagnosed by careful pathological examination of the explant liver. The neonatal presentation of hilar fibropolycystic liver disease can be misdiagnosed as BA.

Congenital and hereditary cystic diseases of the abdomen

Congenital and hereditary cystic lesions of the abdomen are relatively rare. Correct diagnosis is critical as they may simulate several other benign and malignant acquired diseases of the abdomen. With the correct and appropriate use of imaging, diagnosis may be relatively straightforward and clinical management may be implemented appropriately. The purpose of this article is to describe imaging findings of common and uncommon congenital and hereditary cystic disease of the abdominal organs.

Portal hypertension in a patient with biliary hamartomas: A case report

BACKGROUND

Biliary hamartomas (BH) are a rare benign disease caused by malformation of the intrahepatic bile ducts. BH are occasionally diagnosed, but often lack obvious clinical symptoms. They are usually diagnosed by biopsy and imaging tests in clinical practice. Few studies have reported the association of BH with portal hypertension.

CASE SUMMARY

A 40-year-old man was repeatedly admitted to our hospital due to hematochezia. The source of bleeding was considered to be gastroesophageal varices and portal hypertensive gastropathy by endoscopy. He had no history of hepatitis virus infection, alcohol abuse, drug-induced liver injury, or autoimmune liver disease. He underwent magnetic resonance imaging, which showed rounded, irregular, low-signal-T1 and high-signal-T2 lesions diffusely distributed on the liver, that were not communicated with the biliary system on magnetic resonance cholangiopancreatography. According to the imaging examination, the patient was considered to have a diagnosis of BH with portal hypertension.

CONCLUSION

Based on the present case report, BH may be a potential etiology of portal hypertension.