What is the recommended treatment for a gallbladder polyp, especially one larger than 10 mm?

Management of Gallbladder Polyps

For polyps ≥15 mm, immediate surgical consultation for cholecystectomy is recommended; for polyps 10-14 mm, surgical consultation should be considered based on risk factors or evidence of growth; polyps <10 mm generally require surveillance or no follow-up depending on size and morphology. 1, 2

Size-Based Management Algorithm

Polyps ≥15 mm

• Immediate surgical consultation is mandatory regardless of other features. 1, 2
• These polyps have significantly elevated malignancy risk, with neoplastic polyps averaging 18.1 mm compared to 7.5 mm for benign lesions. 1
• The Society of Radiologists in Ultrasound (SRU) consensus strongly supports this threshold based on multiple studies showing size ≥15 mm as an independent predictor of neoplastic transformation. 1

Polyps 10-14 mm

• Surgical consultation should be considered, with the decision influenced by patient risk factors and evidence of growth during surveillance. 1, 2
• If surveillance is chosen over immediate surgery, perform ultrasound follow-up at 6,12, and 24 months. 2, 3
• The absolute cancer risk remains low (0.4% in population studies), but increases substantially with size. 1
• European guidelines recommend cholecystectomy for all polyps ≥10 mm in patients fit for surgery. 3

Polyps 6-9 mm

• Surveillance ultrasound at 6 months, 1 year, and 2 years is recommended if risk factors are present. 3
• Risk factors include: age >60 years, primary sclerosing cholangitis (PSC), Asian ethnicity, and sessile morphology. 3
• If no risk factors are present, no follow-up is required. 1, 2
• The cancer rate for this size range is 8.7 per 100,000 patients. 1

Polyps ≤5-6 mm

• No follow-up is required. 1, 2, 3
• Multiple studies demonstrate 0% malignancy rate in polyps ≤5 mm. 1
• Up to 83% of apparent polyps ≤5 mm are not found at subsequent cholecystectomy, representing pseudopolyps or cholesterol deposits. 1
• The cancer rate is only 1.3 per 100,000 patients for polyps <6 mm. 1

Morphology-Based Risk Stratification

Pedunculated Polyps with Thin Stalks

• These represent extremely low risk lesions. 2
• No follow-up needed if ≤9 mm. 2
• Follow-up at 6,12, and 24 months if 10-14 mm. 2

Sessile Polyps

• Carry higher malignancy risk than pedunculated lesions. 2, 3
• No follow-up needed if ≤6 mm. 2
• Follow-up recommended if >6 mm, even without other risk factors. 2, 3
• Neoplastic lesions are more likely to manifest as focal wall thickening (37.9% of cancers) rather than protruding polyps. 1

Growth as an Indication for Surgery

Rapid Growth

• Growth ≥4 mm within 12 months warrants surgical consultation regardless of absolute polyp size. 2, 4
• This threshold distinguishes pathologic growth from benign fluctuation. 2

Benign Fluctuation

• Minor size changes of 2-3 mm are part of the natural history of benign polyps and should not trigger intervention. 1, 2
• Nearly half of polyps show dynamic size changes over time, with benign growth rates ranging from 0.16-2.76 mm/year. 1, 2
• Growth of 2 mm or more during 2-year follow-up should prompt multidisciplinary discussion considering current size and risk factors. 3

Special Population: Primary Sclerosing Cholangitis

Patients with PSC require more aggressive management due to dramatically elevated gallbladder cancer risk. 1

• Cholecystectomy is recommended for polyps ≥8 mm in PSC patients. 1
• The gallbladder cancer incidence in PSC is 1.1 per 1,000 person-years, with 8.8 per 1,000 person-years in those with radiographically detected polyps. 1
• Approximately 50% of gallbladder masses in PSC patients harbor premalignant or malignant lesions. 1
• Smaller polyps (<8 mm) should undergo contrast-enhanced ultrasound characterization; if contrast-enhancing, cholecystectomy should be considered regardless of size. 1
• Non-contrast-enhancing small polyps require repeat ultrasound at 3-6 months. 1
• Important caveat: Patients with PSC and severe liver decompensation require careful risk-benefit assessment before cholecystectomy due to increased surgical complications. 1

Diagnostic Imaging Approach

Primary Modality

• Transabdominal ultrasound is the first-line imaging modality for detection and surveillance. 3, 5

Advanced Imaging for Characterization

• Contrast-enhanced ultrasound is the preferred method for polyps ≥10 mm when differentiation from tumefactive sludge or adenomyomatosis is challenging. 2
• MRI serves as an alternative if contrast-enhanced ultrasound is unavailable. 2
• Endoscopic ultrasound may provide superior characterization in select cases but is not routinely recommended. 2, 3

Surgical Considerations and Risks

Cholecystectomy Risks

• Surgical morbidity ranges from 2-8%, including bile duct injury risk of 3-6 per 1,000 patients. 1, 2
• Mortality ranges from 2-7 per 1,000 patients, related to operative complexity and comorbidities. 1, 2
• Risk is substantially higher in patients with cirrhosis undergoing hepatocellular carcinoma screening who have incidental polyp detection. 1

Symptomatic Polyps

• Cholecystectomy is recommended for polyps of any size in patients with symptoms potentially attributable to the gallbladder, after excluding alternative causes. 3
• Patients should be counseled that symptoms may persist post-operatively despite polyp removal. 3

Common Pitfalls to Avoid

Overdiagnosis

• 61-69% of polyps seen on ultrasound are not identified at subsequent cholecystectomy. 2
• For polyps ≤5 mm, up to 83% are not found at surgery, representing pseudopolyps. 1

Confusing Tumefactive Sludge with True Polyps

• Small echogenic non-mobile lesions may represent adherent sludge rather than true polyps. 2
• Contrast-enhanced ultrasound can help differentiate true polyps from sludge. 2

Overestimating Malignancy Risk

• The absolute malignancy risk is virtually zero for polyps <5 mm. 2
• Even for polyps 10 mm or larger, the cancer incidence is only 0.4% in population studies. 1
• In a survey of approximately 3 million gallbladder ultrasounds by SRU fellows, no documented cases of malignant polyps <10 mm were identified at initial detection or during follow-up. 1

Inappropriate Extended Surveillance

• Follow-up beyond 3-4 years is not productive for stable polyps. 4
• If a polyp disappears during surveillance, monitoring can be discontinued. 3

Duration of Surveillance

• For polyps requiring surveillance, discontinue follow-up after 2 years in the absence of growth. 3
• Extended surveillance beyond this period has not demonstrated clinical benefit. 4