Gallbladder polyps are elevations in the gallbladder mucosa that project into the gallbladder lumen. Their prevalence is general population is around 5%. Their diagnosis has greatly increased due to the widespread use of abdominal ultrasound. In the majority of patients, the polyps are discovered incidentally.
Types of gallbladder polyps
- Cholesterol polyps
- Inflammatory polyps
- Hyperplastic polyps
- Epithelial polyps (adenomas)
- Mesenchymal tumours
- Malignant (gallbladder carcinomas)
The vast majority of gallbladder polyps are benign and 90% of them are cholesterol polyps.
These are polyps that form because of accumulation of cholesterol in the macrophages in the gallbladder wall. They are covered by the gallbladder columnar epithelium and are attached to the mucosa by a delicate pedicle. Often, they are small and multiple (>3). They have no malignant potential.
These are not common. They are epithelial proliferation with inflammatory infiltration and are often associated with chronic cholecystitis.
These are benign polyps that has a premalignant behaviour. They are pedunculated and often associated with gallstones or chronic cholecystitis. Recent evidence suggests that many gallbladder carcinomas start as benign polyps that progress to carcinoma.
Gallbladder carcinoma has a very poor prognosis. Therefore, it is important to differentiate between benign polyps and malignant or premalignant polyps.
Risk Factors for a polyp to be malignant
- Size > 10 mm
- Age >50 y
- Solitary polyp
- Fast growing polyp
- Sessile polyp
- Concurrent gallstones
- Presence of symptoms
Unfortunately there has been no randomised controlled trial to evaluate the treatment strategies for gallbladder polyps. The two treatment options are cholecystectomy or observation.
My treatment strategy is as follow:
Cholecystectomy: Laparoscopic or Open?
Polyps that are 18 mm or greater are most likely carcinomas. Patients with these polyps should be staged for gallbladder cancer with CT scan and endoscopic ultrasound. Surgery should be done open together with lymph node dissection and excision of the common bile duct with or without liver resection.
In most other instances, cholecystectomy can be done laparoscopically.