Gallbladder (GB) polyps, defined as polypoid lesions arising from the GB mucosa and protruding into the lumen, are increasingly detected due to widespread use of abdominal ultrasonography (US) [1]. Altho-ugh most GB polyps are benign, distinguishing neoplastic polyps with malignant potential is critical for appropriate management [2]. Recent advan-ces in imaging and a better understanding of the natural history of GB polyps have led to significant updates in clinical practice guidelines. In 2022, three major documents were published: the Society of Radiologists in Ultrasound (SRU) consensus con-ference recommendations, the European joint-societal guidelines (ESGAR/EAES/EFISDS/ESGE), and the World Federation of Ultrasound in Medicine and Biology (WFUMB) position paper [3-5]. This review synthesizes these guidelines and contextualizes their application in clinical radiologic practice.

Although the three guidelines use slightly different wordings, their definitions of GB polyps are conceptually aligned. GB polyps are generally defined as nonmobile, nonshadowing lesions arising from the GB mucosa and protruding into the lumen, distinct from gallstones, sludge, mucosal folds, or wall thickening [3-5].

Pathologically, GB polyps are broadly categorized into non-neoplastic and neoplastic lesions. Nonneoplastic polyps, including cholesterol polyps and inflammatory polyps, account for the majority of cases and are typically small with negligible malignant potential. In contrast, neoplastic polyps, including intracholecystic papillary neoplasms and pyloric gland adenomas, are less common but may progress to malignancy or are precursors of malignant tumors [6].

Transabdominal US remains the primary imaging modality for the detection, characterization, and follow-up of GB polyps and is consistently recommended as the first-line examination across all three guidelines [3-5]. Its widespread availability, absence of ionizing radiation, and high detectability for GB lesions make it the cornerstone of clinical evaluation.

The 2022 consensus recommendations from the SRU represent a fundamental shift in the management of GB polyps by introducing a morphology-based risk stratification framework [3]. Unlike prior sizedominant approaches, the SRU guideline emphasizes the importance of polyp morphology as a primary determinant of risk stratification.

Before application of the SRU algorithm, careful assessment of its applicability is required. The guideline explicitly excludes cases in which sonographic evaluation is suboptimal, such as inadequate GB distention or poor sonographic technique. In such scenarios, short-interval follow-up US within 1-2 months is recommended, with efforts to optimize imaging technique and patient preparation. In addition, the algorithm is not applicable when a suspected GB polyp cannot be reliably distinguished from other entities, particularly tumefactive sludge greater than 10 mm or adenomyomatosis. In such cases, further characterization with contrast-enhanced ultrasound (CEUS) or MRI may be considered for further lesion characterization. When imaging findings raise concern for invasive or malignant disease such as evidence of wall invasion, associated hepatic masses, biliary obstruction, or lymphadenopathy, immediate referral for oncologic evaluation is warranted. Importantly, the SRU guideline explicitly excludes patients with primary sclerosing cholangitis (PSC), given their substantially elevated risk of GB malignancy. In this population, management should follow disease-specific recommendations, such as those proposed by the American Gastroenterological Association [7]. Only after these exclusion criteria have been addressed can the SRU morphology-based algorithm be appropriately applied.

Once the algorithm is deemed applicable, risk stratification is performed based on polyp morphology, categorized into three groups: extremely low risk, low risk, and indeterminate risk. Pedunculated polyps exhibiting a “ball-on-the-wall” configuration or those attached by a thin stalk are classified as extremely low risk. In contrast, pedunculated lesions with a thick or wide stalk, as well as sessile polyps, are categorized as low risk. The presence of focal GB wall thickening of 4 mm or greater adjacent to the polyp is considered an indeterminate risk feature.

Following morphologic risk stratification, management is determined according to both risk category and polyp size. In the extremely low-risk category, no follow-up is recommended for polyps measuring 9 mm or less, whereas follow-up US at 6, 12, and 24 months is advised for lesions measuring 10-14 mm. Surgical consultation is recommended for lesions measuring 15 mm or greater, although surgical consultation may also be an acceptable alternative for polyps measuring 10-14 mm. In the low-risk category, no follow-up is recommended for lesions measuring 6 mm or less, whereas polyps measuring 7-9 mm undergo followup US at 12 months. For polyps measuring 10-14 mm, either serial surveillance at 6, 12, 24, and 36 months or surgical consultation may be considered. In contrast, indeterminate risk polyps warrant a more cautious approach. For polyps measuring 6 mm or less, either serial surveillance at 6, 12, 24, and 36 months or surgical consultation may be considered, whereas surgical consultation is advised for polyps measuring 7 mm or greater. Notably, the SRU guideline permits no further follow-up for extremely low-risk polyps up to 9 mm in size, representing a substantially higher threshold than those proposed by the European and WFUMB guidelines, which generally limit no-followup recommendations to lesions measuring 5-6 mm or less.

The 2022 European joint-societal guidelines (ESGAR/EAES/EFISDS/ESGE) provide a structured management strategy for GB polyps, centered on a size-based threshold for surgical intervention. Cholecystectomy is recommended for patients with polypoid lesions measuring 10 mm or more and is suggested for those experiencing symptoms potentially attributable to the GB when no other cause is identified, provided the patient is fit for surgery. For polyps in the 6-9 mm range, surgery is recommended if one or more risk factors for malignancy are present: age over 60 years, a history of PSC, Asian ethnicity, or sessile morphology (including focal wall thickening > 4 mm). Surveillance is reserved for lower-risk scenarios; US follow-up at 6 months, 1 year, and 2 years is recommended for 6-9 mm polyps in patients without risk factors, or for polyps ≤ 5 mm in patients with risk factors. Surveillance may be discontinued after 2 years in the absence of growth. Notably, no follow-up is required for polyps measuring 5 mm or less in patients without risk factors. If a lesion grows to reach 10 mm during the surveillance period, cholecystectomy is advised. Monitoring may be ceased if the lesion disappears during any follow-up examination.

Compared with the previously published European guidelines in 2017 [8], the 2022 updated re-commendations introduce several important changes, particularly with respect to risk stratification and followup duration. The definition of malignancy risk factors has been refined, with the age threshold increased from 50 to 60 years and Asian ethnicity incorporated in place of Indian ethnicity, alongside established factors such as PSC and sessile morphology. In addition, the recommended duration of surveillance has been substantially reduced, with follow-up now limited to a maximum of 2 years, compared with the 5-year period suggested in earlier guidelines.

The 2022 WFUMB position paper provides a framework for managing GB polyps based on weighted US criteria to assess malignancy risk. These sonographic features associated with increased or high risk of malignancy include a solitary presentation, a size of 10 mm or greater, sessile morphology, an irregular or lobulated surface, and evidence of focal GB wall thickening or disruption. The general consensus establishes that patients with polyps measuring at least 10 mm or those experiencing symptoms potentially related to the GB should undergo evaluation for cholecystectomy. For polyps measuring 7-9 mm, follow-up US at 6, 12, and 24 months is advised in patients without additional risk factors or suspicious B-mode US imaging features. However, in the presence of individual risk factors or concerning B-mode US characteristics beyond size, further evaluation with high-resolution US, CEUS, or endoscopic US may be warranted, and surgical management should be considered, particularly in high-risk populations such as those with Indian ethnicity or PSC. For polyps measuring 6 mm or less, no follow-up or treatment is recommended in the absence of risk factors or suspicious imaging findings. In contrast, short-term surveillance at 6, 12, and 24 months may be considered when risk factors or sonographic features associated with increased or high risk of malignancy are present.

The principal similarities and differences among the SRU, European, and WFUMB guidelines are summarized in Table 1.

In conclusion, accumulating evidence over recent years indicates that aggressive surveillance and surgical intervention for incidentally detected small GB polyps are often unwarranted. The 2022 international guidelines reflect this paradigm shift by recommending higher size thresholds for followup and surgical consultation, along with clearly defined criteria for discontinuation of surveillance. These updates are expected to reduce unnecessary ultrasonographic follow-up and surgical interventions, particularly in patients with small, low-risk lesions.