An unusual cause of obstructive jaundice

Clinical History

70-year-old female patient presented with insidious onset painless obstructive jaundice.

Imaging Findings

An abdominal ultrasound examination demonstrated biliary dilatation (images not shown), subsequent to which a magnetic resonance cholangio-pancreatography (MRCP) and an intravenous contrast enhanced computed tomography (CT) abdomen were performed. The images from the MRCP demonstrate moderate intra-hepatic biliary dilatation (short arrows) and common bile duct dilatation (long arrow) secondary to an iso-intense intraluminal filling defect (arrowhead) within the mid to distal CBD (Figs. 1 and 2). The findings are replicated on the CT examination on which the polypoidal intraluminal-filling defect (arrows) demonstrates uniform contrast enhancement (Fig. 3). Finally the patient underwent endoscopic retrograde cholangio-pancreatography (ERCP) and brushings (Fig. 4) of the polypoidal mid to distal CBD mass (arrows), which confirmed the diagnosis of a biliary adenoma. The patient underwent a plastic biliary stent placement at ERCP to relieve biliary obstruction. Currently a resectional surgery has not been planned in this patient due to severe co-morbidities.

Discussion

The accurate diagnosis and management of extra-hepatic bile duct tumours could be very challenging and it is difficult to differentiate between malignant and benign tumours based on imaging findings alone as the appearances/presentation are similar [1]. A benign possibility should be sought after as there is a significant difference in outcome and will help in planning optimal treatment strategy. One should also bear in mind that these benign epithelial tumours of the bile duct have malignant potential.

As per the WHO histological classification [2] of the epithelial tumours of the gallbladder and extra-hepatic ducts are divided into benign (adenomas), intraepithelial neoplasia (dysplasia and carcinoma in situ) and malignant carcinoma. The histological subtypes of bile duct adenomas are tubular, papillary, tubulopapillary, biliary cystadenoma and papillomatosis (adenomatosis). The tubular adenoma is the most common histological type of bile duct adenomas and the usual site of origin is the common bile duct and less commonly it can occur in hepatic, cystic and intra-hepatic biliary ducts [3].

Extra-hepatic bile duct adenomas are quiet rare and there is little literature regarding this condition and most of the available information is from published case reports. Most bile duct adenomas are asymptomatic and incidentally found at surgery. They may occasionally present early with features of obstructive jaundice [3]. Literature review of published case reports by Fletcher et al [1] of biliary adenomas found the spectrum of symptoms varying from obstructive jaundice, bilary colic, right upper quadrant pain, recurrent cholangitis etc.

Biliary adenomas are usually present as solitary intraductal polypoidal lesions within the extra-hepatic biliary tree. On imaging, a well demarcated polypoidal intraluminal lesion with uniform contrast enhancement points to the diagnosis. Upper abdominal lymphadenopathy is not a feature that is associated with this condition.

Surgical resection is the definitive treatment and thought to be curative. There are isolated published case reports of malignant transformation of biliary adenomas [4, 5] but not much in the literature to suggest the actual incidence of malignant. In our case, microscopy showed small tubulopapillary fragments (Fig. 5) containing biliary type epithelium with mostly bland nuclei. Focally there was evidence of mild nuclear crowding amounting to low grade dysplasia (Fig. 5). There was no evidence of high grade dysplasia or invasive malignancy.

Differential Diagnosis List

Final Diagnosis

Common bile duct adenoma -tubulopapillary adenoma with minimal dysplasia.

URL:	https://www.eurorad.org/case/10775
DOI:	10.1594/EURORAD/CASE.10775
ISSN:	1563-4086