Gallbladder polyps are growths that protrude from the inner wall of the gallbladder into its lumen. They are usually found incidentally during an abdominal ultrasound performed for other reasons. While most are harmless, some require surgery to rule out cancer.
How common are gallbladder polyps?
Gallbladder polyps are found in less than 5% of people undergoing biliary tract imaging. The chance of finding polyps increases with age, with the average age at diagnosis being 46 years. Men are slightly more likely to develop them than women.
Types of gallbladder polyps
Gallbladder polyps fall into two broad categories:
These are harmless, non-cancerous lesions. They include:
- Cholesterol polyps — accumulations of cholesterol deposits on the gallbladder wall
- Inflammatory polyps — tissue overgrowth from chronic inflammation
- Adenomyomatosis — a benign thickening of the gallbladder wall that can mimic a polyp
These are rare and have malignant potential. They include:
- Adenomatous polyps (adenomas) — benign but can progress to cancer
- Adenocarcinomas — gallbladder cancer
- Other rare tumours including squamous cell carcinoma, lymphoma and metastases
Symptoms
Most gallbladder polyps cause no symptoms and are found by chance on imaging. When symptoms do occur — such as nausea, vomiting or right-sided abdominal pain — they are usually caused by associated gallstones, tiny gallstones (microcalculi) or a functional gallbladder disorder rather than the polyps themselves.
Diagnosis
The primary tool for diagnosing gallbladder polyps is an abdominal ultrasound. A polyp appears as a fixed lesion projecting from the gallbladder wall into the lumen that does not move when the patient changes position. Unlike gallstones, polyps do not cast an acoustic shadow on ultrasound.
When a polyp is found, the key features assessed are:
- Size — the single most important predictor of cancer risk
- Number — multiple small polyps are usually benign cholesterol polyps; a solitary polyp is more concerning
- Shape — pedunculated (on a stalk) versus sessile (flat-based); sessile polyps carry higher risk
- Growth over time — an increase in size by 2 mm or more between scans warrants attention
If a malignancy is suspected, additional imaging such as CT, MRI or PET scans may be required. Endoscopic ultrasound (EUS) can also be helpful for characterising suspicious lesions and may allow a fine-needle biopsy. It is important to be assessed by a multidisciplinary hepatobiliary cancer team before a biopsy is arranged, as biopsy can increase the risk of local recurrence.
Serum tumour markers (such as CEA and CA 19-9) are not reliable for distinguishing benign from malignant gallbladder polyps, especially when the polyps are small.
When is surgery needed?
The decision to remove the gallbladder (cholecystectomy) depends on the polyp size, characteristics and patient-specific risk factors.
Polyps 10 mm or larger
Laparoscopic cholecystectomy is recommended for gallbladder polyps 10 mm or larger. The risk of malignancy rises significantly beyond this size threshold.
Polyps 5 to 9 mm
Surgery may be recommended if any of the following risk factors are present:
- Primary sclerosing cholangitis (PSC)
- Inflammatory bowel disease
- Sessile (flat) polyp shape
- Asymmetrical gallbladder wall thickening greater than 4 mm
- Age over 50 years
- Increase in polyp size of 2 mm or more on follow-up scans
For uncomplicated 5–9 mm polyps without risk factors, surgery is only offered if the patient is symptomatic.
Polyps smaller than 5 mm
Polyps under 5 mm without concerning features are almost always benign cholesterol polyps. Surgery is rarely needed unless there is growth on surveillance imaging or typical biliary symptoms that cannot be explained by another cause.
Symptomatic patients
For patients with gallbladder polyps smaller than 10 mm who experience typical biliary symptoms (right upper abdominal pain, nausea after fatty meals), laparoscopic cholecystectomy may be offered if no other cause for the symptoms can be identified.
Surveillance of small polyps
Gallbladder polyps that do not require immediate surgery should be monitored with regular ultrasound scans. There are no universally agreed screening intervals, but a practical approach is:
- Polyps 5–9 mm without risk factors: first follow-up ultrasound at 6 months, then annually
- Polyps under 5 mm: follow-up at 12 months
Surgery should be considered if:
- The polyp grows by 2 mm or more since the previous scan
- The polyp reaches 10 mm in size
- The number of polyps increases significantly
- New concerning imaging features develop
Annual ultrasound follow-up is often continued for up to five years after the initial diagnosis. If a polyp disappears during follow-up, no further surveillance is required.
What to expect from surgery
Prof. Mittal performs gallbladder removal using robotic or laparoscopic (keyhole) surgery. The procedure is done through a few small incisions, and most patients go home the same day. After removal, the gallbladder is opened and inspected, then sent for histopathological examination to confirm the polyp type and exclude malignancy.
Recovery
Most people return to normal activities within 1–2 weeks. You will receive personalised advice on diet, activity and wound care before going home. You can live normally without a gallbladder — bile flows directly from the liver to the intestine, and digestion is largely unaffected.