Management of a 6-mm Asymptomatic Gallbladder Polyp
No further intervention is required for this 35-year-old asymptomatic woman with a solitary 6-mm gallbladder polyp. 1, 2, 3
Size-Based Risk Assessment
Polyps ≤6 mm have virtually zero malignancy risk, with large studies documenting 0% malignancy rate in polyps smaller than 5 mm and no documented cases of malignancy in polyps <10 mm at initial detection across approximately 3 million gallbladder ultrasounds. 1, 2, 4
The malignancy risk becomes clinically relevant only at ≥10 mm, where the cancer detection rate is 16.4%, rising to 55.9% for lesions ≥15 mm and 94.1% for lesions ≥20 mm. 5
This patient's 6-mm polyp falls well below any threshold requiring intervention or surveillance. 1, 3
Current Guideline Recommendations
The 2022 European guidelines (ESGAR/EAES/EFISDS/ESGE) explicitly state that patients with no risk factors for malignancy and a gallbladder polyp ≤5 mm require no follow-up. 3 While this patient's polyp is 6 mm, she has no risk factors that would elevate concern:
- Age <60 years (she is 35) 3
- No primary sclerosing cholangitis 3
- Asymptomatic (no symptoms attributable to the gallbladder) 3
- Normal bile ducts and no stones (per ultrasound report) 3
The 2022 Society of Radiologists in Ultrasound consensus further supports this approach, stating that polyps ≤6 mm in the low-risk category require no follow-up. 1, 4
Why Other Options Are Incorrect
Surgical consultation (Option A) is inappropriate because cholecystectomy is only recommended for polyps ≥10 mm, and this patient's 6-mm polyp is well below that threshold. 1, 3 Surgical intervention would expose her to unnecessary operative risks (2-8% morbidity, 0.2-0.7% mortality) without clinical benefit. 6, 4
Liver function tests (Option C) are not indicated as this is an incidental finding in an asymptomatic patient with normal bile ducts. LFTs do not contribute to gallbladder polyp risk stratification and are not part of any guideline-recommended evaluation pathway. 1, 3
Follow-up ultrasound within 6 months (Option D) is not necessary for this size polyp in the absence of risk factors. The European guidelines reserve surveillance for patients with either: (1) 6-9 mm polyps WITH risk factors, or (2) no risk factors but polyps that were initially larger. 3 This patient has a 6-mm polyp with no risk factors, placing her below the surveillance threshold.
Critical Clinical Context
Most small gallbladder polyps are benign cholesterol polyps (60% of all gallbladder polyps), which have negligible malignancy risk and remain static for years. 2, 7, 8
While rare cases of malignant transformation from small polyps have been reported (including one case of a 5-mm polyp becoming malignant over 2 years), these represent exceptional outliers that involved documented growth—a key trigger for intervention. 9
The natural history of small polyps shows that 68% of gallbladder cancers associated with polyps are detected within the first year, and extended surveillance beyond 2-3 years is not productive. 2
Common Pitfall to Avoid
Do not confuse this polyp with tumefactive sludge, which can mimic a polyp on ultrasound but is mobile and layering, whereas true polyps are fixed and non-mobile. 2, 4 The ultrasound report describes a "single polyp," suggesting proper differentiation was made, but if there is any diagnostic uncertainty, a repeat ultrasound after fasting or contrast-enhanced ultrasound could clarify. 1, 2
Answer: B. No further intervention