Background: To determine which polyps of the gallbladder should be operated upon, we investigated the size and number of polyps in resected gallbladders, and studied changes in gallbladder polyps using ultrasonography (US).
Methods: We studied 74 resected gallbladders with small polypoid lesions less than 20 mm in diameter, and 60 patients with gallbladder polyps by US. The polyps in resected gallbladders were classified into four groups histologically, and clinical features, maximum diameter, and number of lesions were compared among the groups. In the followed-up cases with gallbladder polyps, the size and number of polyps were examined by US, and changes during the observation period were studied.
Results: The mean diameter of adenoma was 6.00 +/- 3.39 mm (mean +/- SD) and that of cancer 10.8 +/- 4.16 mm; 97% of cholesterol polyps were less than 10 mm in diameter (3.66 +/- 2.68 mm). Neoplastic polyps tended to be single (adenoma, n = 1.40 +/- 0.89; cancer, n = 1.16 +/- 0.40), whereas half of the cholesterol polyps were multiple (n = 3.09 +/- 3.31). However, when there were fewer than 3 lesions, the incidence of neoplasm was 37% among polyps 5 to 10 mm in diameter. A low incidence (6%) of neoplasm was also observed among polyps less than 5 mm in diameter.
Conclusions: These data indicate that an aggressive surgical approach for small gallbladder polyps is warranted when there are fewer than 3 polyps, regardless of their size.