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Case Reports
. 2020 Oct 6;8(19):4499-4504.
doi: 10.12998/wjcc.v8.i19.4499.

Ascaris-mimicking common bile duct stone: A case report

Seo-Youn Choi  1 , Ha Eun Jo  2 , Yun Nah Lee  3 , Ji Eun Lee  2 , Min Hee Lee  2 , Sanghyeok Lim  2 , Boem Ha Yi  2
Affiliations
Case Reports

Ascaris-mimicking common bile duct stone: A case report

Seo-Youn Choi et al. World J Clin Cases. .

Abstract

Background: In most cases, it is not difficult to differentiate common bile duct (CBD) stone from Ascaris infection because they are different disease entities and have different imaging findings. The two diseases usually demonstrate unique characteristic findings on computed tomography or magnetic resonance cholangiopancreatography. However, we report a rare case from our experience in which a CBD stone mimicked and was misdiagnosed as Ascaris.

Case summary: A 72-year-old male presented with elevated serum liver enzymes. Computed tomography showed a hyper-attenuated, elongated lesion in the CBD lumen and associated biliary inflammation. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography revealed a linear filling defect in the bile duct. Moreover, elongated echogenic material with a central hypoechogenic area was seen on endoscopic ultrasound. Although the imaging findings caused us to suspect infection with the nematode Ascaris, the lesion was revealed to be a dark-brown-colored CBD stone through endoscopic extraction.

Conclusion: We report a rare case of a CBD stone that mimicked Ascaris. We also review the literature for side-by-side comparisons of the imaging features of CBD stones and ascariasis.

Keywords: Ascariasis; Ascaris; Case report; Common bile duct; Gallstones; Magnetic resonance cholangiopancreatography; Multidetector computed tomography.

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Conflict of interest statement

Conflict-of-interest statement: The authors state that they have no conflict of interest.

Figures

Figure 1
Figure 1
A 72-year-old male with a distal common bile duct stone mimicking Ascaris. A and B: Coronal reformatted images of contrast-enhanced computed tomography showed a hyperattenuated, elongated lesion inside the distal common bile duct (CBD) lumen (arrows); C and D: A T2-weighted coronal image revealed a linear filling defect in the distal CBD lumen with mild ductal dilatation, findings that mimic an Ascaris worm; E and F: An elongated tubular filling defect was seen on endoscopic retrograde cholangiopancreatography, and a hyperechoic lesion with a central hypoechoic area was seen on endoscopic ultrasound; G: A dark-brown-colored CBD stone was discovered through endoscopic removal.
Figure 2
Figure 2
Timeline of the patient’s illness. CT: Computed tomography; CBD: Common bile duct; MRCP: Magnetic resonance cholangiopancreatography; ERCP: Endoscopic retrograde cholangiopancreatography; EUS: Endoscopic ultrasound.
See this image and copyright information in PMC

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