Gallbladder polyps on ultrasound: what to measure and when to recommend follow-up
How to tell a polyp from a stone and from biliary sludge, why morphology matters as much as size, and what the SRU and European consensus statements say about follow-up and surgery.
LaudárioUltrasound reports in practice
This article is part of the guide Abdominal Ultrasound: A Guide to the Findings That Actually Change Management.
Gallbladder polyp is a frequent finding and, in the vast majority of cases, benign, almost always a cholesterol polyp. The problem is that the recommendation in the report tends to vary from one examiner to another: one asks for a six-month follow-up of a 3 mm polyp, another does not comment on an 11 mm one. Standardizing the description is what makes it possible to follow current consensus statements.
First: is it really a polyp?
- Stone: hyperechoic, with posterior acoustic shadowing, and moves with a change of decubitus position.
- Biliary sludge: echogenic material without shadowing, which settles in the dependent portion and shifts slowly.
- Polyp: fixed projection from the wall, without shadowing, which does not change position with decubitus.
- Adenomyomatosis: wall thickening with echogenic foci and comet-tail artifact, which should not be mistaken for a polyp.
Repositioning the patient is part of the exam. Without it, an adherent stone and tumefactive sludge become a "polyp" in the report.
What to measure and describe
- Number of polyps and the largest measurement of the largest one.
- Morphology: pedunculated (with a thin stalk or as a "ball on the wall") or sessile (broad base).
- Focal thickening of the wall adjacent to the polyp.
- Vascularity on Doppler, when assessable.
- Comparison with the prior study, with the earlier measurement.
What the consensus statements recommend
The Society of Radiologists in Ultrasound (SRU, 2022) consensus stratifies by morphology. In summary:
- Pedunculated (extremely low risk): up to 9 mm need no follow-up; from 10 to 14 mm, ultrasound surveillance; from 15 mm, surgical evaluation.
- Sessile or broad-based (low risk): up to 6 mm need no follow-up; above that, surveillance, and surgical evaluation for the larger ones.
- Focal thickening of the wall adjacent to the polyp is a higher-risk criterion and indicates surgical evaluation.
The European consensus (ESGAR and associated societies, 2022) is more conservative: it indicates cholecystectomy from 10 mm and, between 6 and 9 mm, when there are risk factors such as age over 60 years, primary sclerosing cholangitis, Asian ethnicity or a sessile base.
Because the two documents differ, a useful report gives size and morphology, which are the data that either pathway uses, and leaves management to the treating physician when the recommendation is not consensual.
Common errors
- Not changing the decubitus position and calling an adherent stone or sludge a polyp.
- Describing "small polyps" without a measurement.
- Omitting whether the polyp is pedunculated or sessile.
- Recommending follow-up for every polyp, including those the consensus statements exempt.
See also our text on gallbladder and cholelithiasis.
How Laudário helps
In the abdomen templates of Laudário:
- Gallbladder with stones, sludge and polyps in separate fields.
- Polyp measurement and morphology recorded for comparison.
- Follow-up recommendation on its own tab.
Try it for 15 days free, no credit card required.
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