Gas-containing rim-calcified gallstones

Case contributed by Dustin Roberts

Presentation

Non-localizing abdominal pain on background of obesity

Patient Data

Age: 65 years
Gender: Female

Several multifaceted rim-calcified gallstones of varying sizes are present within the gallbladder.
The common bile duct diameter is at the upper limits of normal. No gallstones are seen within the common bile duct. 
There is a gas-filled stone near the gallbladder neck revealing a “Mercedes-Benz” sign (arrow).

Case Discussion

Incidental finding of uncomplicated cholelithiasis with several large, rim-enhancing multifaceted gallstones. One stone reveals the classic “Mercedes-Benz” sign, seen as a triradiate pattern of central gas-containing fissures as described.

Around 50% of gallstones contain some amount of fissuring, but few contain gas and are less commonly visible on imaging. Rim calcification is more common in pigment gallstones due to higher biliary calcium concentrations, and is thought to be a result of chronic common bile duct obstruction and low-grade gallbladder wall inflammation.

The three types of gallstones include: 1) cholesterol (10%), 2) pigment (10%), and 3) mixed (80%).  Cholesterol stones contain >50% cholesterol and form with supersaturation of bile. Pigment stones are comprised of mostly bile and contain less than 20% cholesterol. If rim calcifications are seen, they are usually pigment stones.

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Case information

rID: 61224
Published: 5th Jul 2018
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included
Institution: David Geffen School of Medicine

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