Cystic neoplasms of bile ducts are rare tumours. Localexcision is usually associated with high recurrence rate. Liverresection with adequate bile duct margin is the ideal surgicaltreatment.

We present a rare case of papillary cystadenocarcinomaof left extrahepatic bile duct and discuss the relevant clinicalmanagement.

Case Summary

A 47-year-old male, chronic alcoholic was admitted withanorexia, weight loss and jaundice of 6 months duration.Clinical examination was unremarkable. Investigationsrevealed raised serum alkaline phosphatase levels (212 IU/L). Ultrasound abdomen showed a 5.5 cm X 3.3 cm irregularmass in the region of the porta with dilated common bileduct. A possibility of hilar cholangiocarcinoma wasconsidered. CT scan abdomen (Figure 1) revealed a 5.2 cmX 4.5 cm mixed density lesion in the left lobe of the liver withobstruction at the level of the porta hepatis with intrahepaticbile duct dilatation. Magnetic resonance cholangiographyrevealed a cystic mass in the fissure of ligamentum teres,compatible with biliary cystadenoma.



A laparotomy was performed. Intraoperative findingsincluded bile duct dilatation with bulky head of pancreas.There was a cystic lesion involving the extrahepatic part ofthe left hepatic duct. The cyst wall was sent for frozen sectionexamination which was suggestive of mucinous cystadenomaof bile duct with high suspicion of malignancy.

After performing cholecystectomy, intraoperative cholangiography was performed through the cystic ductstump, the pathology was confined to the left hepatic ductand the right ductal system was normal with free flow ofcontrast into the duodenum. A left hepatectomy was performedpreserving the caudate lobe; a 1 cm margin of normal bileduct was obtained. Postoperatively, the patient made asmooth recovery and was discharged on the fifthpostoperative day.

Histopathologically, on gross appearance (Figure 2), thebiliary system of the left lobe was dilated, a large greyishpink, friable and irregular growth 3.3 cm X 3.5 cm was presentwithin the lumen of the left hepatic duct adherent in part to thebile duct. The hepatic ducts were dilated up to periphery ofliver. Microscopy revealed a malignant tumour with papillaryand glandular pattern; the lining cells were cuboidal withround nuclei and mild nuclear pleomorphism (Figure 3).There was no   mesenchymal stroma. The tumour infiltratedthe wall of the hepatic duct and extended up to the liver, thesurrounding liver showed markedly widened portal tract, withmoderately dense inflammatory infiltrates in the portal tractsalong with bile duct proliferation. The bile duct margin wasfree of tumour. The findings were compatible with biliarypapillary cystadenocarcinoma.





Discussion

Biliary cystic neoplasms (cystadenomas and malignantcystadenocarcinomas) are rare tumours with a reportedincidence of less than 0.1% in autopsy studies.[1] A vast majority of biliary cystadenocarcinomas (around 90%) occur in theintrahepatic ducts. Cystadenocarcinomas of the extrahepaticbile duct are exceedingly rare with a few case reports.[2,3,4]

The origin of cystic tumours remains unknown. Theyprobably arise either from aberrant hamartamous bile ductsor ectopic remnants of foregut but this theory does not accountfor the mucinous material usually found in cystadenoma.[5] Ithas been hypothesized that cystadenocarcinomas result frommalignant degeneration of pre-existing cystadenomas andthis has been supported by demonstration of benignepithelium in more than 90 % of these tumours.[6]

Biliary cystic neoplasms are most commonly seen inmiddle aged women. These tumours are often diagnosedincidentally during investigations for nonspecific symptomslike upper abdominal discomfort or pain, anorexia, nauseaor abdominal mass.

Preoperative distinction between adenoma and carcinomais difficult on clinical or radiological basis. The ultrasoundexamination of the liver reveals common features includinganechoic cystic mass with internal echoes or a hypo echoicmass with echogenic septae.[7] On contrast enhanced CTscan, there is a multiloculated mass with papillary infoldings.Septa, mural nodules and the density of the wall may enhanceon IV contrast. These tumours are often situated deeply andamongst the vital vascular structures at the porta hepatisand hence may not be amenable to safe percutaneous biopsy.The intraoperative frozen sections have only a limited accuracyto differentiate adenoma from carcinoma.[8]

On histology, cystadenomas are lined by a single layer ofcuboidal to tall columnar cells with mucin secretingepithelium resting on a basement membrane.[9] There are two subgroups depending on the presence or absence ofmesenchymal (ovarian-like) stroma. Cystadenoma/carcinoma with mesenchymal stroma (CMS) was firstdescribed by Wheeler and occurs exclusively in females.[9] Cystadenoma/ carcinoma without mesenchymal stromaoccur  both in males and females and usually behavesaggressively compared to CMS.[8] Cystadenocarcinoma showsmultilayered malignant epithelium with numerous papillaryprojections.

Local excision is often performed for extrahepatic biliarycystadenocarcinomas. However, this operation is associated with local recurrence of up to 50%.[10] The literature oncystadenocarcinomas of extrahepatic bile ducts is verylimited.  Probably major liver resections are indicated to obtaina negative margin. The differentiation between adenoma andcarcinoma is not usually possible, either preoperatively oreven on frozen sections intraoperatively. Hence, the currentrecommended treatment for these tumours is resection ofthe affected hepatic lobe.

References

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