Background and study aims: The purpose of this study was to assess the accuracy of endoscopic ultrasonography (EUS) in making a differential diagnosis of small (< or = 20 mm in diameter) polypoid lesions of the gallbladder, and to construct an EUS scoring system.
Patients and methods: The EUS findings were retrospectively analyzed in 70 surgical cases of small polypoid lesions classified into two groups: neoplastic (adenocarcinoma in 11, and adenoma in 7), and non-neoplastic (cholesterol polyp in 44, inflammatory polyp in 7 and fibrous polyp in 1). The EUS variables were the maximum diameter and height/width ratio of the largest polyps, echo level, internal echo pattern, surface patterns, number and shape of polyps, presence of hyperechoic spotting, complication of gallbladder stones. The EUS data were used for the construction of an EUS scoring system to ascertain the risk of neoplasia.
Results: Three EUS variables, i. e. tumor maximum size, internal echo pattern, and hyperechoic spotting were statistically significant according to multivariate analysis using stepwise logistic regression models (P < 0.01, P < 0.05, and P < 0.01, respectively). The total EUS score based on the coefficient of multivariate analysis was as follows: (maximum diameter in mm) + (internal echo pattern score; where heterogeneous = 4, homogeneous = 0) + (hyperechoic spot[s] score; where presence = - 5, absence = 0). According to our EUS scoring system, the sensitivity, specificity, and accuracy for the risk of neoplastic polyps with scores of 12 or higher were 77.8 %, 82.7 % and 82.9 %, respectively.
Conclusions: The EUS scoring system will be a useful means of differentiating between neoplastic and non-neoplastic polyps of the gallbladder.