Medline ® Abstracts for References 2,3,5,6

Nine patients with calcification of the gallbladder wall (porcelain gallbladder) were analyzed by ultrasound and the appearance correlated with the CT, radiographic, clinical, and surgical findings. Three distinct patterns were identified: (a) a hyperechoic semilunar structure with acoustic shadowing posteriorly, simulating a stone-filled gallbladder devoid of bile, which was seen in 5 patients; (b) a biconvex , curvilinear echogenic structure with variable acoustic shadowing, seen in all 3 patients with carcinoma of the gallbladder; and (c) an irregular clump of echoes with posterior acoustic shadowing, seen in 1 patient. Potential pitfalls in the diagnosis of gallbladder calcification are presented, and the association between calcification and cancer is emphasized.

BACKGROUND: Gallbladder cancer is the most common biliary tract malignancy. Calcification of the gallbladder wall is reported to be associated with gallbladder cancer. In the literature, the incidence is quoted to be between 12% and 61%. This study aims to clarify the risk of cancer in a calcified gallbladder.

METHODS: The charts and pathology reports at the Massachusetts General Hospital were reviewed, and patients with either gallbladder cancer or a calcified gallbladder were included in the study. The Fisher exact test was used to test for the association between cancer and gallbladder wall calcifications.

RESULTS: From 1962 to 1999, there were approximately 25,900 gallbladder specimens analyzed at the Massachusetts General Hospital. There were 150 patients with gallbladder cancer and 44 patients with calcified gallbladders. Two types of calcified gallbladders were noted: those with complete intramural calcification (n = 17) and those with selective mucosal calcification (n = 27). The incidence of cancer arising in a gallbladder with selective mucosal wall calcification was approximately 7%. There was a significant association between gallbladder cancer and selective mucosal calcification with an odds ratio of 13.89 (P =.01). There were no patients with diffuse intramural calcification and cancer.

CONCLUSIONS: A calcified gallbladder is associated with an increased risk of gallbladder cancer, but at a much lower rate than previously estimated. The incidence of cancer depends on the pattern of calcification; selective mucosal calcification poses a significant risk of cancer whereas diffuse intramural calcification does not.