Antenatal sonographic diagnosis of choledochal cyst: Case report and imaging review

Congenital anomalies of the gastrointestinal tract: the liver, extrahepatic biliary tree and pancreas

Congenital anomalies of the liver, biliary tree and pancreas are rare birth defects, some of which are characterized by a marked variation in geographical incidence. Morphogenesis of the hepatobiliary and pancreatic structures initiates from two tubular endodermal evaginations of the most distal portion of the foregut. The pancreas develops from a larger dorsal and a smaller ventral outpouching; emergence of the two buds will eventually lead to the fusion of the duct system. A small part of the remaining ventral diverticulum divides into a "pars cystica" and "pars hepatica", giving rise to the cystic duct and gallbladder and the liver lobes, respectively. Disruption or malfunctioning of the complex mechanisms leading to the development of liver, gallbladder, biliary tree and pancreas can result in numerous, albeit fortunately relatively rare, congenital anomalies in these organs. The type and severity of anomalies often depend on the exact moment in which disruption or alteration of the embryological mechanisms takes place. Many theories have been brought forward to explain their embryological basis; however, no agreement has yet been reached for most of them. While in some cases pathological evaluation might be more centered on macroscopic evaluation, in other instances small biopsies will be the keystone to understanding organ function and treatment results in the context of congenital anomalies. Thus, knowledge of the existence and histopathological characteristics of some of the more common conditions is mandatory for every pathologist working in the field of gastrointestinal pathology.

Differentiation of cystic biliary atresia and choledochal cysts using prenatal ultrasonography

Purpose

This study explored the performance of prenatal ultrasonography in the differential diagnosis of cystic biliary atresia (CBA) and choledochal cyst (CC).

Methods

Fetuses diagnosed with hepatic hilar cyst in the second trimester were included in this study. A series of prenatal ultrasound examinations were performed in the second and third trimesters. The diameter of the gallbladder (GB) and hepatic cyst were measured, as well as the wall thickness of the GB. The GB-cyst connection, visibility of the right hepatic artery (RHA), and other concomitant abnormalities were carefully evaluated. A neonatal transabdominal ultrasound examination was performed within 1 week after birth, and clinical data were followed up to 6 months after birth.

Results

Between January 1, 2016 and January 31, 2020, 53 fetuses diagnosed with hepatic hilar cyst were recruited. Eight were excluded because they were lost to follow-up. Among the 45 cases included in this study, 10 were diagnosed with CBA and 35 with CC after birth. Statistically significant differences were found in GB width, wall thickness, change in GB width, change in cyst length, GB-cyst connection, and RHA visibility between the CBA and CC groups. GB width showed the best diagnostic performance with an area under the curve (AUC) of 0.899. The combination of GB width, GB wall thickness, and GB-cyst connection yielded a comparable AUC of 0.971.

Conclusion

The GB should be carefully evaluated in fetuses with hepatic hilar cyst. Prenatal ultrasound findings could provide suggestive parameters for the differential diagnosis of CBA from CC.

Prenatal sonographic diagnosis of biliary tract malformations

Congenital anomalies of the biliary tract include a variety of pathologic conditions, such as biliary atresia, choledochal cysts, gallbladder agenesis, congenital cholelithiasis, and gallbladder duplication. Although most of these malformations are rare and benign conditions, they may occasionally represent a major threat to extrauterine life. Visualization of a normal-sized gallbladder should be a mandatory component of the second-trimester anomaly ultrasound scan. Advances in prenatal sonography enable the detection of biliary tract congenital malformations. In this review, we discuss the detection rates, sonographic features, and prognosis of the most frequently prenatally diagnosed biliary tract malformations.

A rare case of choledochal cyst with pancreas divisum: case presentation and literature review

Choledochal cysts are rare congenital malformations of the bile duct characterized by dilatations of the intrahepatic and/or extrahepatic portion of the biliary tree, they are associated to an anomalous arrangement of the pancreaticobiliary duct. Pancreas divisum results from a fusion failure of the pancreatic buds. The coexistence of pancreas divisum and choledochal cyst in adults has been reported in less than 10 well documented cases. This article presents a case of a 42-year-old Peruvian man with intermittent episodes of abdominal pain, initially diagnosed with choledocholithiasis, who underwent open cholecystectomy. During surgery, a diagnosis of choledochal cyst and pancreas divisum was made, and therefore a hepaticoduodenostomy was performed. The patient was referred to our hospital due to persistence of abdominal pain. After admission, a papillectomy was achieved without further complications. A cyst resection and dismantling of hepaticoduodenostomy with Roux-en-Y was performed 8 years later. During the subsequent 18-month follow-up, the patient remains asymptomatic.

Ultrasound and differential diagnosis of fetal abdominal cysts

The present study aimed to investigate the use of ultrasound and differential diagnosis to diagnose a fetal abdominal cyst. A retrospective analysis of 41 cases of fetal abdominal cyst, which included ovarian cysts, choledochal cysts, intestinal duplication and mesenteric cysts, was performed. Imaging characteristics of various types of cysts were summarized, compared and discussed. Among 41 fetal abdominal cyst cases, there were 21 cases of ovarian cysts, 11 cases of bile duct cyst, six cases of intestinal duplication and three cases of mesenteric cyst. Each type of fetal cyst had its own distinctive characteristics on abdominal ultrasound examination. Ovarian cysts were located at one side of the bladder, round-shaped and observed in female fetuses; choledochal cysts were located in the hilar, were oblong- or oval-shaped and connected to the bile duct; intestinal duplication was located in the middle of abdomen, close to the intestine, and presented as an intestinal wall-like structure; mesenteric cysts were round-shaped with thin tensionless wall, presented with multiple chambers, and were easily deformable on compression. The findings of the present study demonstrated that a comprehensive analysis of the association between the cyst and its adjacent location, shape, wall thickness, motility and other aspects of dynamic changes via ultrasonography may provide a differential diagnosis of different types of fetal abdominal cysts.