Type VI choledochal cyst – An emerging rare entity (11th pediatric case of type VI) with a review of literature

A Sushma; Rajeev Redkar; Rahul Deo Sharma; Surendra Singh; Sonia Thakur; Asha Mary George

doi:10.4103/jiaps.jiaps_144_23



REVIEW ARTICLE

Year : 2023 \| Volume : 28 \| Issue : 6 \| Page : 453-456

Type VI choledochal cyst – An emerging rare entity (11^th pediatric case of type VI) with a review of literature

A Sushma¹, Rajeev Redkar¹, Rahul Deo Sharma¹, Surendra Singh¹, Sonia Thakur¹, Asha Mary George²
¹ Department of Paediatric Surgery, Lilavati Hospital and Research Centre, Mumbai, Maharashtra, India
² Consultant Histopathologist, Lilavati Hospital and Research Centre, Maharashtra, India

Date of Submission	27-Jun-2023
Date of Decision	07-Jul-2023
Date of Acceptance	29-Jul-2023
Date of Web Publication	15-Sep-2023

Correspondence Address:
Rajeev Redkar
Department of Paediatric Surgery, Lilavati Hospital and Research Centre, Bandra West, Mumbai - 400 050, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jiaps.jiaps_144_23

Abstract

Choledochal cysts (CCs) are abnormal dilatations of the biliary system. Usually, CCs are classified into five types. The sixth type (Type VI) is an emerging and rare type, reported the first case in 1991. We report this rare CC, Type VI seen in our experience for the first time. We have also reviewed the literature; only 26 cases of Type VI were found, including adults and children, ever since the first case has been reported in 1991. To the best of our knowledge, this is the 11^th pediatric case report of a Type VI choledochal cyst.

Keywords: Magnetic resonance pancreaticogram, Meckel's diverticulum, Type VI choledochal cyst

How to cite this article:
Sushma A, Redkar R, Sharma RD, Singh S, Thakur S, George AM. Type VI choledochal cyst – An emerging rare entity (11^th pediatric case of type VI) with a review of literature. J Indian Assoc Pediatr Surg 2023;28:453-6

How to cite this URL:
Sushma A, Redkar R, Sharma RD, Singh S, Thakur S, George AM. Type VI choledochal cyst – An emerging rare entity (11^th pediatric case of type VI) with a review of literature. J Indian Assoc Pediatr Surg [serial online] 2023 [cited 2023 Dec 9];28:453-6. Available from: https://www.jiaps.com/text.asp?2023/28/6/453/386439

Introduction

Choledochal cysts (CCs) are rare congenital dilatations of the biliary system. CCs are traditionally classified into five types.^[1] The 6^th type of CC has been described as cystic dilatation of the cystic duct. The first of these well-documented cases dates from 1983,^[2] and its inclusion as a sixth type was proposed in 1991.^[3] Although some authors consider it a subtype of II, subtype VIa has recently been proposed for isolated CD dilation, and VIb if there are other associated cysts, mainly of the main bile duct (MBD).^[4] Data on Type VI CCs are limited, with about 26 cases reported to date.

Here, we report a case of Type VI CC confirmed intraoperatively, managed by cyst resection with bile duct reconstruction by means of Roux-en-Y hepaticojejunostomy (RYHJ).

[TAG:2]Case Report [/TAG:2]

A 15-month-old male child was brought with nonbilious vomiting. He was evaluated with ultrasound (USG) abdomen, which showed fusiform dilatation of the right hepatic duct, the common hepatic duct (CHD), and the proximal common bile duct (CBD), with mildly contracted and involuted gallbladder (GB) with echogenic sludge within. An oval thin-walled cystic structure was also seen of about 20 mm × 9 mm with echogenic sludge within it, inferomedial to the GB, representing a significantly dilated cystic duct joining the proximal CBD, findings suspicious of CC Type IVA with involvement of the cystic duct (Type VI). Magnetic resonance pancreaticogram (MRCP) with magnetic resonance (MR) abdomen confirmed the findings of CC Type IV showing a maximum width of 8–9 mm with no intraductal filling defect/calculus. A 20 mm × 13 mm cystic lesion is noted on the right side of the CBD, communicating with the CBD, representing fusiform dilatation of the cystic duct (Type VI)/saccular diverticulum from the CBD (Type II) [Figure 1] with the unremarkable distal CBD. The rest of the abdominal scan was normal. His liver function test results were as follows: alkaline phosphatase 290 U/L, aspartate aminotransferase 30 U/L, alanine aminotransferase 16 U/L, gamma-glutamyl transferase 10 U/L, and total bilirubin 0.83 mg/dL. The coagulation profile was PT/INR-12 s/1.09. Other blood tests were: serum amylase 187 U/L and serum lipase 20.7 U/L.

Figure 1: (a-c) shows magnetic resonance cholangiopancreatogram showing gallbladder (marked by blue indicator) and dilatation of the cystic duct (marked by yellow indicator), with dilated common bile duct suggestive of Type VIb choledochal cyst

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We planned for surgical management after thorough bowel preparation with polyethylene glycol, enemas, and gut sterilization with ofloxacin-metronidazole. A rooftop incision was taken with the liver made free from all the ligamentous attachments. A giant GB was seen with the cystic duct dilated [Figure 2]. Intraoperative cholangiogram showed dilated cystic duct with the GB distended, dilatation of the right hepatic duct, CHD, and proximal CBD suggestive of Type VI CC (Type VI b).

Figure 2: Intraoperative image showing dilated choledochal cyst (marked in the blue indicator)

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Cholecystectomy with cyst excision and distal CBD suturing was done. Choledochoscope was placed in the confluence of the CHD. The area was irrigated with normal saline, and debris was cleaned. Biliary reconstruction with RYHJ was carried out with a Roux loop of 40 cm length with an abdominal drain placement. A wedge liver biopsy was taken. An associated Meckel's diverticulum, which was noted with abnormal feeling mucosa, was excised. The postoperative period was uneventful. The drain was removed on the postoperative day 6. Amylase levels (>7500 U/L) and lipase levels (>3000 U/L) were raised from the GB bile. Amylase (136 U/L) and lipase (1093 U/L) from the CBD bile were lower than GB bile. Postoperatively, the patient remained stable, and recovery was smooth.

Microscopically, the liver had normal histology with no fibrosis (fibrosis score-0/6) and well-glycogenated hepatocytes with no features of hepatitis. GB showed focally unremarkable mucosal folds with denuded lining epithelium and markedly congested lamina propria showing sparse lymphocytic infiltrates. The dilated cystic duct was lined by biliary-type epithelium with uniform nuclei. The cyst wall shows fibrocollagenous and fibrohyalinized tissue with mild lymphocytic and eosinophilic inflammatory infiltrates with patchy aggregates of and congested vessels and areas of fibrosis. The CBD and CHD cut margins are unremarkable, suggestive of CC with mild chronic inflammation without dysplasia [Figure 3]. Based on intraoperative morphology and histopathology, a diagnosis of Type VIb CC was given. Meckel's diverticulum showed small intestinal mucosa with maintained villous and crypt architecture with mild lymphoid hyperplasia. After 4 months of follow-up, the patient is healthy and asymptomatic.

Figure 3: H and E image with scanner view showing choledochal cyst wall with biliary-type lining epithelium (marked by yellow arrows all along the epithelial side)

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Discussion

The Todani classification of CCs was published in 1977, and five CC [CC] types were identified.^[1]

Type I - Saccular dilatation of the CBD with no involvement of the intrahepatic ducts
Type II - Diverticula of the extrahepatic biliary tree from the liver to the duodenum
Type III - Dilatation of the pancreatic part of the CBD
Type IV - Multiple cysts of both the intrahepatic and extrahepatic biliary trees
Type V - Dilatation of the intrahepatic biliary ducts.

A PubMed search was conducted using the search terms “CC of cystic duct” and “type VI CC”. Twenty-six cases were found, including adults and children. [Table 1] shows the list of 26 Type VI CCs and their evaluation and management with respective reported authors.^[5] So far, only 10 cases of this Type VI CCs are reported in children in the literature. This is the 11^th pediatric case report of Type VI CC.

Table 1: List of reported Type VI cases in adults and children (highlighted in yellow) and their management

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The classic triad of jaundice, pain in the right hypochondrium, and palpable mass are only present in 20% of patients, with at least two of the three manifestations occurring in 80% of children and only in 25% of adults.^[6]

The diagnosis is usually confirmed intraoperatively and can be challenging to diagnose on preoperative imaging. The initial diagnostic modalities preferred include USG abdomen complemented with hepatobiliary MR and cholangio-resonance imaging. However, to confirm the diagnosis, intraoperative cholangiography or endoscopic retrograde cholangiopancreatography may be indicated further. In our case, we have done USG followed by MRCP as preoperative diagnostic imaging and intraoperatively IOC to confirm the diagnosis. In our case, the intraoperative cholangiogram showed the dilated extrahepatic biliary system with cystic dilatation of the cystic duct as well as dilatation of the right and left hepatic ducts, CHD, and proximal CBD, which is classified as Type VIb CC by Serena et al.^[3]

Type VIa CCs, which are isolated cystic duct CCs, are typically managed with cholecystectomy. The differential diagnosis includes gallbladder duplication and duplicated bile duct.

In Type VIb, the surgical extension will depend on the union of the cystic duct cyst with the CBD. In cases with a segment of normal CD at the union with the MBD, as well as in those where the breadth of this union between the cyst-CD and the CBD is not too wide, cholecystectomy with excision of the cyst and CD is sufficient from the oncological point of view.^[7] If there is the involvement of the CBD or the drainage of the cyst to the CBD is excessively wide, total excision of the extrahepatic BD and bilioenteric reconstruction should be performed, usually with RYHJ.^[6],[7],[8]

On inspection, the cystic duct was largely dilated with a wide base involving the CHD and the proximal CBD. Hence, we performed cholecystectomy with the excision of the dilated cystic duct, and biliary reconstruction was done with hepaticojejunostomy. Malignant transformation of these cysts is described in the literature, with an overall rate of malignancy ranging from 5% to 7.5%, with the highest rates reported in Types I and IV, and the lowest rates in Types II and III.^[9]

The associated anomalies in the literature are also limited. To the best of our knowledge, Meckel's diverticulum in our case is the first reported associated anomaly with Type VI CC.

In our case, histopathology also confirmed the CC of the dilated cystic duct, CHD, and proximal CBD with normal liver histology. The changes of fibrosis and ulceration of the mucosa help in the differentiation of the CC from the proximal duct dilatation due to distal obstruction.

Conclusion

CCs of the cystic duct are rare presentations. Although they represent a subtype of Type II CCs based on the Todani classification, one needs to understand this variant to create awareness among pediatricians, pediatric surgeons, and hepatobiliary surgeons, which helps them in diagnosis and definitive treatment. Abdominal ultrasound and MRCP are the preoperative imaging studies of choice. Intraoperative cholangiogram and the visual findings confirm the Type VI CC, which is further classified into Type VIa and Type VIb. Treatment of Type VIa involves cholecystectomy. Whereas, in case of Type VIb, an additional bile duct excision and biliary reconstruction with hepaticojejunostomy may be required in wide-based cysts involving the CBD as in our case. An associated Meckel's diverticulum is also the first reported anomaly with Type VI CC, as in our case.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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