An Unusual Ring-Shaped Gallstone Mimicking Porcelain Gallbladder in a Patient with Chronic Kidney Disease: A Case Report

Background: Porcelain gallbladder is associated with a higher prevalence of malignancy. Prophylactic cholecystectomy is suggested for both symptomatic and asymptomatic patients. Although gallstones are very commonly observed in clinical practices, it is recommended in asymptomatic patients. However, a ring-shaped gallstone may be easily mistaken with porcelain gallstone and requires further investigation using computed tomography (CT) to avoid the unnecessary risks of surgery. Case Presentation: A 71-year-old female with renal dysfunction and diabetes mellitus had a ring-shaped calcification confirmed by abdominal CT scan in Taichung city of Taiwan, in 2016. She had already been followed up for at least seven years. In addition to traditional risk factors, authors believe that renal dysfunction may have also predisposed her to the development of a gallstone. The differential diagnosis of porcelain gallbladder and only ring-shaped gallstone is very important due to different treatments and outcomes. The more attractive part of this case was that the ring-shaped gallstone is rare in clinical practices. Conclusions: For patients with a ring-shaped calcification, clinicians should rule out porcelain gallbladder since such a diagnosis would indicate an increased risk of gallbladder carcinoma.