Purpose: To determine the natural history of gallbladder (GB) polyps incidentally detected at ultrasonography (US) and to propose management guidelines for these lesions based on polyp size.
Materials and methods: The HIPAA-compliant study was approved by the institutional review board, and informed consent was waived. A database search for "polyp" in all US examinations of the GB between January 1, 1999, and December 31, 2001, at a single institution was performed. All subsequent US reports were reviewed to determine changes in GB polyp size. The electronic medical record was searched to obtain clinical and pathologic follow-up.
Results: Three hundred forty-six patients (mean age, 51.6 years; range, 20-93 years) with GB polyps were included. There were 156 men (45%) and 190 women (55%). US follow-up (mean, 5.4 years; range, 2-11.5 years) was performed in 149 patients (43%). Polyp size was stable in 90 (60%) polyps, decreased in eight (5%), increased in one (1%), and resolved in 50 (34%). Forty-two patients (12%) underwent cholecystectomy, revealing 13 (31%) GBs with polypoid lesions, 24 (57%) with stones and no polyps, and five (12%) with neither a stone nor a polypoid lesion. Clinical follow-up (mean, 8 years; range, 5-10.4 years) was performed in 155 patients (45%). No patient had clinical evidence of GB-related disease. Overall, no cases of GB malignancy were identified in 346 patients. Mean polyp size was 5.0 mm (range, 1-18 mm). No neoplastic polyps were found at 1-6 mm, one neoplastic polyp was seen at 7-9 mm, and two neoplastic polyps were found at 10 mm or larger.
Conclusion: The risk of GB malignancy resulting from incidentally detected polyps is extremely low. Incidentally detected GB polyps measuring 6 mm or less may require no additional follow-up. Data are inconclusive regarding polyps 7 mm or greater, and further studies are warranted.
© RSNA, 2010