Gallbladder polyps are growths that form on the inner lining of the gallbladder, a small organ located beneath the liver that stores bile. These growths are frequently discovered incidentally during imaging tests performed for other conditions. While most gallbladder polyps are not serious, understanding their nature and potential implications is important.
Understanding Gallbladder Polyps
Gallbladder polyps are projections from the mucous membrane lining the gallbladder wall. The majority of these polyps are benign, meaning they are non-cancerous and typically do not cause symptoms.
Various types of gallbladder polyps exist, with cholesterol polyps being the most prevalent, accounting for 60% to 90% of cases. These are not true growths but rather deposits of cholesterol that adhere to the gallbladder wall. Inflammatory polyps, which represent scar tissue from chronic inflammation, make up about 5% to 10% of cases. Other types include adenomyomatosis, an overgrowth of the gallbladder lining, and adenomas, which are true tumors with a small potential to become cancerous.
Assessing the Risk
The potential seriousness of a gallbladder polyp primarily relates to its risk of malignancy, or developing into cancer. Polyp size is a significant factor in this assessment; polyps larger than 10 millimeters (1 centimeter) generally carry a higher likelihood of being cancerous or becoming cancerous over time. Polyps smaller than 7 millimeters, however, typically pose no increased risk of gallbladder cancer.
The rate at which a polyp grows also provides important information, as a rapid increase in size can indicate a higher risk. A growth rate exceeding 2 millimeters per year may suggest a neoplastic (potentially cancerous) polyp. Patient age is another consideration, as the risk of gallbladder cancer increases with older age. Additionally, polyps that are solitary rather than multiple, and those accompanied by gallstones, may warrant closer attention.
Detection and Follow-Up
Gallbladder polyps are often discovered by chance during imaging studies performed for other reasons, as most do not cause noticeable symptoms. Abdominal ultrasound is the most common and widely used imaging test for detecting these growths. Other imaging techniques, such as CT scans or MRI, may be used for more detailed evaluation, especially if there is concern about the polyp’s nature.
Once a gallbladder polyp is identified, monitoring is frequently recommended, particularly for smaller polyps that are not immediately concerning. This involves watchful waiting with periodic ultrasound examinations to track changes in size or appearance. For polyps 5 millimeters or less without other risk factors, follow-up may not be required. However, for polyps between 6 and 9 millimeters, surveillance with ultrasound at 6 months, 1 year, and 2 years is often suggested. Continued monitoring is crucial if any risk factors are present, or if the polyp shows growth.
Management and Treatment Options
Treatment for gallbladder polyps depends on their characteristics, particularly size and growth. Many polyps, especially the common cholesterol polyps, require no intervention beyond regular monitoring. If a polyp is large, growing, causes symptoms, or has features suggesting a higher risk of malignancy, surgical removal of the gallbladder, known as a cholecystectomy, is typically recommended.
Guidelines often suggest cholecystectomy for polyps measuring 10 millimeters or larger due to their increased association with gallbladder cancer. Surgery may also be considered for smaller polyps if they are symptomatic, or if other risk factors for malignancy are present, such as older age or coexisting gallstones. The procedure is commonly performed laparoscopically, which is a minimally invasive approach involving small incisions. While the gallbladder is not considered an essential organ, its removal is the only known method to eliminate the polyps themselves.