Diagnosis and Treatment of Gallbladder Polyps: Current Perspectives

Prediction of neoplastic gallbladder polyps in patients with different age level based on preoperative ultrasound: a multi-center retrospective real-world study

BACKGROUND

The prevalence of neoplastic polyps in gallbladder polyps (GPs) increases sharply with age and is associated with gallbladder carcinoma (GBC). This study aims to predict neoplastic polyps and provide appropriate treatment strategies based on preoperative ultrasound features in patients with different age level.

METHODS

According to the age classification of WHO, 1523 patients with GPs who underwent cholecystectomy from January 2015 to December 2019 at 11 tertiary hospitals in China were divided into young adults group (n=622), middle-aged group (n=665) and elderly group (n=236). Linear scoring models were established based on independent risk variables screened by the Logistic regression model in different age groups. The area under ROC (AUC) to evaluate the predictive ability of linear scoring models, long- and short- diameter of GPs.

RESULTS

Independent risk factors for neoplastic polyps included the number of polyps, polyp size (long diameter), and fundus in the young adults and elderly groups, while the number of polyps, polyp size (long diameter), and polyp size (short diameter) in the middle-aged groups. In different age groups, the AUCs of its linear scoring model were higher than the AUCs of the long- and short- diameter of GPs for differentiating neoplastic and non-neoplastic polyps (all P<0.05), and Hosmer-Lemeshow goodness of fit test showed that the prediction accuracy of the linear scoring models was higher than the long- and short- diameter of GPs (all P>0.05).

CONCLUSION

The linear scoring models of the young adults, middle-aged and elderly groups can effectively distinguish neoplastic polyps from non-neoplastic polyps based on preoperative ultrasound features.

Diagnosis and treatment of gallbladder polypoid lesions: Current practices and future prospects

ABSTRACT

Gallbladder polypoid lesions (GPLs) refer to any elevated lesion of the mucosal surface of the gallbladder wall, and the prevalence is estimated to be between 0.9% and 12.1%. GPLs include benign polyps and malignant polyps. Benign polyps are further classified as non-neoplastic polyps and neoplastic polyps. Cholesterol polyps are the most common benign polyps and adenocarcinoma is the main type of malignant polyp. Hepatitis B virus infection, liver function abnormalities, dyslipidemia, and obesity are the main risk factors for GPLs. Studies of biological mechanisms have focused on malignant gallbladder polyps, the development of which is regulated by hormone levels in vivo , gut microbiota, inflammation, oxidative stress, Salmonella typhimurium , and related molecules. Diagnostic modalities include chemical examination and imaging examination, with imaging examination currently being the mainstay. Treatment of patients with GPLs is based on the presence or absence of symptoms, age, size of the polyps, tendency of the polyp to increase, and risk factors for symptomatic malignancy to determine whether surgery should be performed.

Is ultrasonography accurate for the diagnosis of gallbladder polyps? A review of cholecystectomy specimens from patients diagnosed with gallbladder polyps over a 14-years period

INTRODUCTION

Incidence of gallbladder polyps is 0,3-12%. It is important to differentiate pseudopolyps (cholesterol polyps, adenomyomatosis, inflammatory polyps), which do not have the capacity to become malignant, from true polyps (adenomas and adenocarcinomas). The main risk factors for malignancy are >6-10 mm, growth, sessile morphology, Indian ethnicity and primary sclerosing cholangitis. Ultrasound is the gold standard for diagnosis. Most polyps diagnosed by ultrasound are pseudopolyps. The main objective of this study is to analyse whether ultrasound is accurate for diagnosing true polyps in patients undergoing surgery for this reason.

METHODS

Retrospective observational study with prospective data entry of patients undergoing elective cholecystectomy for gallbladder polyps from 2007 to 2021. Surgery was indicated in symptomatic patients and in those with risk factors. The study has been approved by the Clinical Research Ethics Committee of our hospital.

RESULTS

We included 124 patients in our study. An elective laparoscopic cholecystectomy was performed in all of them. The mean age was 55,4 years and 61% were women. Of all patients, 65% were symptomatic at diagnosis. Only 3 patients had true polyps (2,4%). All of them were tubular adenomas. The rest of patients were false positives (97,6%). The adenoma size was 11, 6 and 5 mm, respectively. The surgical indication was due to polyp size or due to associated biliary symptoms.

CONCLUSION

Ultrasonography is not accurate for the diagnosis of gallbladder polyps. Validation of other complementary tests for the diagnosis of gallbladder polyps in asymptomatic patients could be relevant to avoid unnecessary surgeries.

Detection of Gallbladder Disease Types Using Deep Learning: An Informative Medical Method

Nowadays, despite all the conducted research and the provided efforts in advancing the healthcare sector, there is a strong need to rapidly and efficiently diagnose various diseases. The complexity of some disease mechanisms on one side and the dramatic life-saving potential on the other side raise big challenges for the development of tools for the early detection and diagnosis of diseases. Deep learning (DL), an area of artificial intelligence (AI), can be an informative medical tomography method that can aid in the early diagnosis of gallbladder (GB) disease based on ultrasound images (UI). Many researchers considered the classification of only one disease of the GB. In this work, we successfully managed to apply a deep neural network (DNN)-based classification model to a rich built database in order to detect nine diseases at once and to determine the type of disease using UI. In the first step, we built a balanced database composed of 10,692 UI of the GB organ from 1782 patients. These images were carefully collected from three hospitals over roughly three years and then classified by professionals. In the second step, we preprocessed and enhanced the dataset images in order to achieve the segmentation step. Finally, we applied and then compared four DNN models to analyze and classify these images in order to detect nine GB disease types. All the models produced good results in detecting GB diseases; the best was the MobileNet model, with an accuracy of 98.35%.

A Bayesian network model to predict neoplastic risk for patients with gallbladder polyps larger than 10 mm based on preoperative ultrasound features

BACKGROUND

Polyp size of 10 mm is insufficient to discriminate neoplastic and non-neoplastic risk in patients with gallbladder polyps (GPs). The aim of the study is to develop a Bayesian network (BN) prediction model to identify neoplastic polyps and create more precise criteria for surgical indications in patients with GPs lager than 10 mm based on preoperative ultrasound features.

METHODS

A BN prediction model was established and validated based on the independent risk variables using data from 759 patients with GPs who underwent cholecystectomy from January 2015 to August 2022 at 11 tertiary hospitals in China. The area under receiver operating characteristic curves (AUCs) were used to evaluate the predictive ability of the BN model and current guidelines, and Delong test was used to compare the AUCs.

RESULTS

The mean values of polyp cross-sectional area (CSA), long, and short diameter of neoplastic polyps were higher than those of non-neoplastic polyps (P < 0.0001). Independent neoplastic risk factors for GPs included single polyp, polyp CSA ≥ 85 mm ², fundus with broad base, and medium echogenicity. The accuracy of the BN model established based on the above independent variables was 81.88% and 82.35% in the training and testing sets, respectively. Delong test also showed that the AUCs of the BN model was better than that of JSHBPS, ESGAR, US-reported, and CCBS in training and testing sets, respectively (P < 0.05).

CONCLUSION

A Bayesian network model was accurate and practical for predicting neoplastic risk in patients with gallbladder polyps larger than 10 mm based on preoperative ultrasound features.

Value of Conventional Ultrasound-based Scoring System in Distinguishing Adenomatous Polyps From Cholesterol Polyps

BACKGROUND AND AIM

Ultrasound has increased the detection of gallbladder polyps, but it has limitations in evaluating the nature of gallbladder polyps, especially the maximum size of 1.0 to 1.5 cm. We assessed the value of ultrasound scoring system based on independent predictive parameters in distinguishing adenomatous polyps from cholesterol polyps with the maximum size of 1.0 to 1.5 cm.

MATERIALS AND METHODS

We enrolled 163 patients with gallbladder polyps (1.0 to 1.5 cm) who underwent ultrasonography and cholecystectomy. Ultrasound image characteristics were compared between cholesterol polyps and adenomatous polyps in the training cohort from April 2018 to January 2020. An ultrasound scoring system was constructed in the training cohort, and its diagnostic performance was evaluated in the validation cohort from February 2020 to February 2021.

RESULTS

Maximum size, height/width ratio, stone or sludge, vascularity, and hyperechoic spot were significantly different between cholesterol polyps and adenomatous polyps in the training cohort ( P <0.05). The independent predictive parameters for adenomatous polyps were lower height/width ratio, presence of vascularity and absence of hyperechoic spot. The total score was as follows: (height/width ratio, <0.9=4, ≥0.9=0) + (vascularity, present=3, absent=0) + (hyperechoic spot, absent=2, present=0). The sensitivity, specificity and accuracy of ultrasound scoring system ≥5 for diagnosis of adenomatous polyps in the validation cohort were 73.33%, 80.49%, and 78.57%, respectively.

CONCLUSIONS

The ultrasound scoring system aids in distinguishing adenomatous polyps from cholesterol polyps, and effectively decreasing unnecessary cholecystectomy.

Value of prediction model in distinguishing gallbladder adenoma from cholesterol polyp

BACKGROUND AND AIM

Gallbladder adenomatous polyp is a pre-cancerous neoplasm, and it is difficult to classify from cholesterol polyps before cholecystectomy. The study aimed to clarify the risk characteristics of gallbladder adenomas and establish a prediction model to differentiate gallbladder adenomas from cholesterol polyp lesions.

METHODS

From May 2019 to December 2021, the patients underwent cholecystectomy in the Shanghai Eastern Hepatobiliary Surgery Hospital were retrospectively reviewed. According to the permanent pathology test, the patients were divided into adenomas and cholesterol polyps groups. All the included cases received ultrasound equipment examinations before cholecystectomy and their clinical information were completely recorded. Then the patients' baseline characteristics and ultrasound imaging variables were analyzed by logistic regression. Finally, a predictive model for gallbladder adenomas will be established and assessed based on the independent risk factors.

RESULTS

A total of 423 cases including 296 cholesterol polyps and 127 gallbladder adenomas were analyzed in detail. Multivariate logistic regression analysis revealed that solitary polyp lesion (OR = 2.954, 95% CI 1.759-4.960, P < 0.001), the maximal diameter of lesions (OR = 1.244, 95% CI 1.169-1.324, P < 0.001), and irregular shape of polyp lesions (OR = 5.549, 95% CI 1.979-15.560, P = 0.001) were the independent predictive factors of gallbladder adenomas. According to the results, regression equation of logit(P) = -3.828 + 1.083*number of gallbladder polyps lesions (GPLs) + 0.218*diameter of GPLs + 1.714*shape of GPLs was established. Area under the curve (AUC) was 0.828 (95% CI 0.782-0.874, P < 0.001). When logit P > 0.204, the sensitivity of estimating adenoma was 79.5%, the specificity of recognizing adenoma was 70.6%, and the whole correct ratio was 73.3%. While the AUC of diameter (10 mm) being a predictive factor in this study was only 0.790 (95% CI 0.741-0.839, P < 0.001). And the sensitivity and specificity of 10 mm as the optimal diagnostic cutoff value to diagnose adenomas were 74.8% and 65.9%, respectively.

CONCLUSIONS

The risk factors of solitary polyp lesion, larger diameter, and irregular morphology feature of polyp lesions were significantly related to gallbladder adenomas. And the predictive model established in the study can effectively identify adenomas from cholesterol polyps and help patients to select the optimal treatment protocol.

A New Risk Scoring System to Predict Malignancy in Gallbladder Polyps: a Single-Center Study

OBJECTIVE

Ultrasonography (US) is the most commonly used radiological method in the diagnosis of gallbladder polyps (GBPs). Patients diagnosed with GBPs on US are operated on with risk factors that do not have a high level of evidence. Our aim in this study is to determine the sensitivity of US in diagnosis GBPs, to define risk factors for neoplastic (NP) polyps, and to develop the risk scoring system.

MATERIALS AND METHODS

Between July 2011 and July 2021, 173 patients who were found to have GBPs in the pathology specimens after cholecystectomy were included in the study. Patients were divided into two groups: nonneoplastic and NP groups.

RESULTS

GBPs in patients who underwent abdominal US for any reason was 4.5%. The sensitivity of US in the diagnosis of GBPs was 56.6%. Comparison between groups, age ≥50, presence of symptoms, polyp size >12.5mm, single polyp, concomitant gallstones, and gallbladder wall thickness ≥4mm were statistically in the NP group. A risk scoring system was developed using these values. If the risk score was <4, 0.6% of GBPs was NP polyps. If the risk score was ≥4, 63.2% of GBPs were NP polyps.

CONCLUSION

Our risk scoring system can prevent unnecessary choelcystectomy. Because the incidence of NP polyps in low-risk patients (risk score <4) is extremely rare.

Risk of developing gallbladder cancer in patients with gallbladder polyps detected on transabdominal ultrasound: a systematic review and meta-analysis

OBJECTIVE

To estimate the risk of malignancy in gallbladder polyps of incremental sizes detected during transabdominal ultrasound (TAUS).

METHODS

We searched databases including MEDLINE, Embase, and Cochrane Library for eligible studies recording the polyp size from which gallbladder malignancy developed, confirmed following cholecystectomy, or by subsequent follow-up. Primary outcome was the risk of gallbladder cancer in patients with polyps. Secondary outcome was the effect of polyp size as a prognostic factor for cancer. Risk of bias was assessed using the Quality in Prognostic Factor Studies (QUIPS) tool. Bayesian meta-analysis estimated the median cancer risk according to polyp size. This study is registered with PROSPERO (CRD42020223629).

RESULTS

82 studies published since 1990 reported primary data for 67,837 patients. 67,774 gallbladder polyps and 889 cancers were reported. The cumulative median cancer risk of a polyp measuring 10 mm or less was 0.60% (99% credible range 0.30-1.16%). Substantial heterogeneity existed between studies (I2 = 99.95%, 95% credible interval 99.86-99.98%). Risk of bias was generally high and overall confidence in evidence was low. 13 studies (15.6%) were graded with very low certainty, 56 studies (68.3%) with low certainty, and 13 studies (15.6%) with moderate certainty. In studies considered moderate quality, TAUS monitoring detected 4.6 cancers per 10,000 patients with polyps less than 10 mm.

CONCLUSION

Malignant risk in gallbladder polyps is low, particularly in polyps less than 10 mm, however the data are heterogenous and generally low quality. International guidelines, which have not previously modelled size data, should be informed by these findings.

ADVANCES IN KNOWLEDGE

This large systematic review and meta-analysis has shown that the mean cumulative risk of small gallbladder polyps is low, but heterogeneity and missing data in larger polyp sizes (>10 mm) means the risk is uncertain and may be higher than estimated.Studies considered to have better methodological quality suggest that previous estimates of risk are likely to be inflated.

[Differential diagnosis of gallbladder polypoid lesions by micro-flow imaging]

OBJECTIVE

To explore the value of micro-flow imaging (MFI) in evaluating blood flow characteristics and differential diagnosis of gallbladder polypoid lesions.

METHODS

We retrospectively analyzed the clinical data and ultrasound images of 73 patients with gallbladder polypoid lesions, including 24 patients with pathologically confirmed neoplastic polyps (n=24) and 49 with non-neoplastic polyps (n=49). All the patients underwent conventional ultrasound, MFI and contrast enhanced ultrasound (CEUS) before cholecystectomy. The blood flow characteristics of the lesions in color Doppler flow imaging (CDFI) and MFI were compared, and the consistency of the findings by these two modalities with those of CEUS were evaluated by weighted Kappa consistency test. The diagnostic performance of MFI for gallbladder polypoid lesions was assessed.

RESULTS

There were significant differences between MFI and CDFI in the evaluation of blood flow characteristics of gallbladder polypoid lesions (χ²=37.684, P < 0.001). MFI showed better performance than CDFI in displaying the blood flow characteristics of the polyps. The consistency in the findings was 0.118 between CDFI and CEUS and 0.816 between MFI and CEUS. The sensitivity, specificity and accuracy of MFI in distinguishing neoplastic polyps from non-neoplastic polyps were 75.00%, 93.88% and 87.67%, respectively.

CONCLUSION

MFI has a good consistency with CEUS in displaying the blood flow characteristics of gallbladder polypoid lesions and can accurately distinguish neoplastic polyps from non-neoplastic polyps, thus providing new ultrasound diagnostic evidence to support clinical decisions on optimal treatments of gallbladder polypoid lesions.

Diagnostic performance of endoscopic ultrasound-artificial intelligence using deep learning analysis of gallbladder polypoid lesions

BACKGROUND AND AIM

Endoscopic ultrasound (EUS) is the most accurate diagnostic modality for polypoid lesions of the gallbladder (GB), but is limited by subjective interpretation. Deep learning-based artificial intelligence (AI) algorithms are under development. We evaluated the diagnostic performance of AI in differentiating polypoid lesions using EUS images.

METHODS

The diagnostic performance of the EUS-AI system with ResNet50 architecture was evaluated via three processes: training, internal validation, and testing using an AI development cohort of 1039 EUS images (836 GB polyps and 203 gallstones). The diagnostic performance was verified using an external validation cohort of 83 patients and compared with the performance of EUS endoscopists.

RESULTS

In the AI development cohort, we developed an EUS-AI algorithm and evaluated the diagnostic performance of the EUS-AI including sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. For the differential diagnosis of neoplastic and non-neoplastic GB polyps, these values for EUS-AI were 57.9%, 96.5%, 77.8%, 91.6%, and 89.8%, respectively. In the external validation cohort, we compared diagnostic performances between EUS-AI and endoscopists. For the differential diagnosis of neoplastic and non-neoplastic GB polyps, the sensitivity and specificity were 33.3% and 96.1% for EUS-AI; they were 74.2% and 44.9%, respectively, for the endoscopists. Besides, the accuracy of the EUS-AI was between the accuracies of mid-level (66.7%) and expert EUS endoscopists (77.5%).

CONCLUSIONS

This newly developed EUS-AI system showed favorable performance for the diagnosis of neoplastic GB polyps, with a performance comparable to that of EUS endoscopists.

Gallbladder Polyps Increase the Risk of Ischaemic Heart Disease Among Korean Adults

Background: Gallbladder (GB) polyps and ischaemic heart disease (IHD) share some common risk factors. We investigated the longitudinal effects of gallbladder (GB) polyps, as a surrogate metabolic indicator, on IHD.

Methods: We enrolled 19,612 participants from the health risk assessment study (HERAS) and Korean Health Insurance Review and Assessment Service (HIRA) database. The primary outcome was IHD, which consisted of angina pectoris (ICD-10 code I20) or acute myocardial infarction (ICD-10 code I21) that occurred after enrolment into the study. We calculated hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD according to the presence of GB polyps using multivariate Cox proportional hazards regression models.

Results: The median follow-up period was 29.9 months and a total of 473 individuals (2.4%, 473/19,612) developed IHD. Individuals with GB polyps had an increased risk of IHD compared with the control group after adjusting for potential confounding variables (HR = 1.425; 95% CI, 1.028–1.975). Furthermore, the coexistence of hypertension or dyslipidaemia resulted in an increased risk (HR = 2.14, 95% CI, 1.34–3.44 or HR = 2.09, 95% CI, 1.32–3.31, respectively) of new-onset IHD in the GB polyp group.

Conclusions: GB polyps was an independent risk factor of IHD. Awareness of these associations will inform clinicians on the need to include cardiovascular risk management as part of the routine management of patients with GB polyps.

The diagnostic value of high-frequency ultrasound combined with color Doppler ultrasound versus surgical pathology in gallbladder polyps

OBJECTIVE

This study aimed to analyze the value of high-frequency ultrasound combined with color Doppler ultrasound in the diagnosis of gallbladder polyps.

METHODS

A retrospective analysis was performed on 108 patients with gallbladder polyps, all of whom were examined by high-frequency ultrasound and color Doppler ultrasound with surgical or pathological findings as the gold standard.

RESULTS

Taking surgical pathology findings as the gold standard, the diagnostic accuracy, sensitivity and specificity of high-frequency ultrasound for gallbladder polyps were 63.89%, 63.27%, and 70.00%, respectively. The diagnostic accuracy, sensitivity and specificity of color Doppler ultrasound were 74.07%, 73.47%, and 80.00%, respectively. The diagnostic accuracy, sensitivity and specificity of high-frequency ultrasound combined with color Doppler ultrasound were 91.67%, 90.82%, and 100.00%, respectively. The proportion of mulberry-like or papillary projections was 56.18% in 89 benign lesions diagnosed by high-frequency ultrasound combined with color Doppler ultrasound, the proportion of hyperechoic lesion was 47.19%, and the proportion of single lesion was 59.55%. The incidence rate of blood flow signal was 26.97% in 89 benign lesions, including 10 cases of punctiform blood flow signal, 9 cases of band-like blood flow signal and 5 cases of multiple stones in the lumen of the gallbladder.

CONCLUSION

High-frequency ultrasound combined with color Doppler ultrasound has high accuracy in the diagnosis of gallbladder polyps, and can yield better diagnostic results than either method, which can be used as an optional method for the diagnosis of gallbladder polyps.

Diffuse Gallbladder Adenomyomatosis in a Child

Adenomyomatosis of the gallbladder is a benign condition, usually occurring in middle age, in which the epithelium of the gallbladder proliferates and the gallbladder wall thickens with the presence of Rokitansky-Aschoff sinuses (RAS). The diffuse form is an unusual subtype of adenomyomatosis. Herein, we describe a 17-year-old female who presented with dull and intermittent pain in the right hypochondriac region for more than a month. Ultrasound followed by magnetic resonance imaging showed marked diffuse gallbladder wall thickening. A gross cholecystectomy specimen showed a diffusely enlarged gallbladder. The final diagnosis of gallbladder adenomyomatosis (GA) was confirmed by the histopathologic appearance of muscular and epithelial hyperplasia, contributing to mural thickening with epithelial invaginations forming the pathognomonic intramural diverticula known as the RAS. This case highlights that the diffuse form of GA is uncommon and is often accompanied by chronic inflammation, sometimes requiring differential diagnosis from gallbladder malignancies, especially when there is no image showing a “comet tail” of cholesterol crystals in the wall.

[Gallbladder polyps: modern approaches to diagnostics and treatment]

Gallbladder polyps are an elevation of the mucous membrane that protrudes into the lumen of the gallbladder cavity. Their prevalence in the general population varies from 0.3 to 13.8%. According to the modern classification, polyps of the gallbladder are divided into benign non-tumor, benign tumor and malignant tumor polyps. A review of modern literature presents cohort and randomized controlled trials, including those summarized in meta-analyzes and systematic reviews, suggesting that the dominant form of polypoid formations of the gallbladder are cholesterol pseudo-polyps with no malignant potential associated with impaired cholesterol metabolism, often combined with gallbladder cholesterosis, metabolic syndrome and cardiovascular morbidity. Evidence is building up on the effectiveness of ursodeoxycholic acid for controlling components of the metabolic syndrome and cardiovascular risks. Ursodeoxycholic acid preparations may become promising for the management of cholesterol polyps.

Fatty liver is an independent risk factor for gallbladder polyps

BACKGROUND

Gallbladder polyps (GBPs) are known to be associated with obesity and metabolic diseases. However, to date, the relationship between GBPs and abnormal body fat distribution, such as fatty liver, visceral obesity, or sarcopenia, has not yet been established.

AIM

To evaluate whether GBPs are associated with fatty liver, visceral obesity, or sarcopenia.

METHODS

We retrospectively reviewed the medical records of subjects who underwent various laboratory tests, body composition measurement with a non-invasive body composition analyzer, and abdominal ultrasonography during health checkups. A total of 1405 subjects with GBPs were compared with 2810 age- and sex-matched controls.

RESULTS

The mean age of the subjects was 46.8 ± 11.7 years, and 63.8% were male. According to multiple logistic regression analysis, the presence of fatty liver [odds ratio (OR) 1.413; 95% confidence interval (CI) 1.218-1.638; P < 0.001] was an independent risk factor for GBP, together with low levels of alanine aminotransferase (OR 0.993; 95%CI 0.989-0.996; P < 0.001). Additionally, fatty liver showed both independent (OR 1.629; 95%CI, 1.335-1.988; P < 0.001) and dose-dependent (moderate to severe fatty liver; OR 2.137; 95%CI, 1.662-2.749; P < 0.001) relationship with large GBPs (≥ 5 mm). The presence of sarcopenia and high visceral fat area were not significantly associated with GBPs.

CONCLUSION

Fatty liver was found to be closely associated with GBPs irrespective of sarcopenia and visceral obesity.

Gallbladder polyps: evolving approach to the diagnosis and management

Gallbladder (GB) polyp is a mucosal projection into the GB lumen. With increasing health awareness, GB polyps are frequently found using ultrasonography during health screening. The prevalence of GB polyps ranges between 1.3% and 9.5%. Most patients are asymptomatic and have benign characteristics. Of the nonneoplastic polyps, cholesterol polyps are most common, accounting for 60%-70% of lesions. However, a few polyps have malignant potential. Currently, the guidelines recommend laparoscopic cholecystectomy for polyps larger than 1 cm in diameter due to their malignan potential. The treatment algorithm can be influenced by the size, shape, and numbers of polyps, old age (>50 years), the presence of primary sclerosing cholangitis, and gallstones. This review summarizes the commonly recognized concepts on GB polyps from diagnosis to an algorithm of treatment.

Effect of gallbladder polyp size on the prediction and detection of gallbladder cancer

BACKGROUND

Gallbladder polyps are relatively common. Although most gallbladder polyps are benign, some are malignant. Current guidelines state that malignancy should be suspected for polyps ≥ 10 mm in diameter. We clarified the cancer detection rates in accordance with the size distribution of gallbladder polyps, and evaluated the effectiveness of the reported risk factors in predicting malignancy.

METHODS

In this retrospective case-control study, our institutional database was searched to identify patients who underwent laparoscopic cholecystectomy for benign or malignant gallbladder polyps at Sada Hospital, Japan. The chi-squared test was used to analyze the risk factors for malignancy.

RESULTS

There were 227 protruding gallbladder lesions. The 206 benign polyps had a diameter of 2-21 mm, while the 21 malignant polyps were 7-60 mm. The cancer detection rates were 16.4% for lesions ≥ 10 mm, 55.9% for lesions ≥ 15 mm, and 94.1% for lesions ≥ 20 mm. Of the benign lesions, cholesterol polyps were the most frequent (50-100%) in all size ranges, even in large lesions (≥ 15 mm). The sessile lesion morphology was significantly more frequent in malignant (60%) than benign lesions (3.4%, p < 0.00001). Multiple polyps were frequently diagnosed not only as cholesterol polyps (81.1%), but also as adenomas (60%); adenomas were found as a single adenoma within other types of polyps. There were two cases of malignant small gallbladder polyps (< 10 mm); these lesions met the surgical indications of a size increase during observation or a sessile morphology.

CONCLUSIONS

The cancer detection rate increased significantly with an increase in the lesion size. Risk factors such as a sessile polyp morphology or an increase in lesion size were effective in predicting malignancy for small gallbladder polyps. It might be difficult to accurately predict the pathologic diagnoses of gallbladder polyps preoperatively, as cholesterol polyps were most frequent, even in the large size range.