Non-neoplastic Polyps of the Gallbladder: A Clinicopathologic Analysis of 447 Cases

Preliminary study on diagnosis of gallbladder neoplastic polyps based on contrast-enhanced ultrasound and grey scale ultrasound radiomics

Objective

Neoplastic gallbladder polyps (GPs), including adenomas and adenocarcinomas, are considered absolute indications for surgery; however, the distinction of neoplastic from non-neoplastic GPs on imaging is often challenging. This study thereby aimed to develop a CEUS radiomics nomogram, and evaluate the role of a combined grey-scale ultrasound and CEUS model for the prediction and diagnosis of neoplastic GPs.

Methods

Patients with GPs of ≥ 1 cm who underwent CEUS between January 2017 and May 2022 were retrospectively enrolled. Grey-scale ultrasound and arterial phase CEUS images of the largest section of the GPs were used for radiomics feature extraction. Features with good reproducibility in terms of intraclass correlation coefficient were selected. Grey-scale ultrasound and CEUS Rad-score models were first constructed using the Mann-Whitney U and LASSO regression test, and were subsequently included in the multivariable logistic regression analysis as independent factors for construction of the combined model.

Results

A total of 229 patients were included in our study. Among them, 118 cholesterol polyps, 68 adenomas, 33 adenocarcinomas, 6 adenomyomatoses, and 4 inflammatory polyps were recorded. A total of 851 features were extracted from each patient. Following screening, 21 and 15 features were retained in the grey-scale and CEUS models, respectively. The combined model demonstrated AUCs of 0.88 (95% CI: 0.83 - 0.93) and 0.84 (95% CI: 0.74 - 0.93) in the training and testing set, respectively. When applied to the whole dataset, the combined model detected 111 of the 128 non-neoplastic GPs, decreasing the resection rate of non-neoplastic GPs to 13.3%.

Conclusion

Our proposed combined model based on grey-scale ultrasound and CEUS radiomics features carries the potential as a non-invasive, radiation-free, and reproducible tool for the prediction and identification of neoplastic GPs. Our model may not only guide the treatment selection for GPs, but may also reduce the surgical burden of such patients.

RadioGraphics Update: New Follow-up and Management Recommendations for Polypoid Lesions of the Gallbladder

Editor's Note.-RadioGraphics Update articles supplement or update information found in full-length articles previously published in RadioGraphics. These updates, written by at least one author of the previous article, provide a brief synopsis that emphasizes important new informaion such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes.

Incidental Findings of Gallbladder and Bile Ducts-Management Strategies: General Aspects, Gallbladder Polyps and Gallbladder Wall Thickening-A World Federation of Ultrasound in Medicine and Biology (WFUMB) Position Paper

The World Federation of Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings with a series of position papers to give advice on characterization and management. The biliary system (gallbladder and biliary tree) is the third most frequent site for incidental findings. This first part of the position paper on incidental findings of the biliary system is related to general aspects, gallbladder polyps and other incidental findings of the gallbladder wall. Available evidence on prevalence, diagnostic work-up, malignancy risk, follow-up and treatment is summarized with a special focus on ultrasound techniques. Multiparametric ultrasound features of gallbladder polyps and other incidentally detected gallbladder wall pathologies are described, and their inclusion in assessment of malignancy risk and decision- making on further management is suggested.

A Case of Lymphoid Hyperplasia of the Gallbladder Extending to the Bile Duct

A 72-year-old woman was referred for the examination of wall thickening of the bile duct and a polyp-like lesion on the gallbladder. The bile duct and gallbladder lesions were observed to be continuous on abdominal ultrasonography. We performed a bile duct biopsy, and pathological findings showed hyperplasia of the lymphoid follicles without malignancy. We considered these two lesions to be the same lesion, and laparoscopic cholecystectomy was performed to make a definite diagnosis. The pathological examination of the resected gallbladder also showed hyperplasia of the lymphoid follicles. We diagnosed the patient with lymphoid hyperplasia of the gallbladder extending to the bile duct.

A nomogram-based model and ultrasonic radiomic features for gallbladder polyp classification

BACKGROUND AND AIM

Gallbladder polyps (GBPs) are relatively common. Many studies have attempted to distinguish between benign and neoplastic GBPs to identify early-stage gallbladder carcinoma. We have established an accurate neoplastic predictive model and evaluated the effectiveness of radiomics in predicting malignancy in patients with GBPs.

METHODS

A total of 503 patients confirmed through postoperative pathology were included in this retrospective study. Clinical information and ultrasonographic findings were retrospectively analyzed. The model was constructed from independent risk factors using Spearman correlation and logistic regression analysis of a training cohort of 250 GBP patients, and its efficacy was verified using an internal validation group of 253 consecutive patients through the receiver operating characteristic curve (ROC). The area of GBPs was delimited manually, and the texture features of ultrasound images were analyzed using correlation and ROC analysis.

RESULTS

Independent predictors, including age, gallstones, carcinoembryonic antigen, polyp size, and sessile shape, were incorporated into the nomogram model for the neoplastic potential of GBPs. Compared with other proposed prediction methods, the established nomogram model showed good discrimination ability in the training group (area under the curve [AUC]: 0.865) and validation group (AUC: 0.845). Regarding ultrasonic radiomics, the minimum caliper diameter was identified as the only independent predictor (AUC: 0.841).

CONCLUSIONS

Our preoperative nomogram model can successfully evaluate the neoplastic potential of GBPs using simple clinical data, and our study verified the use of radiomics in GBP identification, which may be valuable for avoiding unnecessary surgery in patients.

A Nomogram-based Model to Predict Neoplastic Risk for Patients with Gallbladder Polyps

BACKGROUND AND AIMS

Gallbladder polyp (GBP) assessment aims to identify the early stages of gallbladder carcinoma. Many studies have analyzed the risk factors for malignant GBPs. In this retrospective study, we aimed to establish a more accurate predictive model for potential neoplastic polyps in patients with GBPs.

METHODS

We developed a nomogram-based model in a training cohort of 233 GBP patients. Clinical information, ultrasonographic findings, and blood test findings were analyzed. Mann-Whitney U test and multivariate logistic regression analyses were used to identify independent predictors and establish the nomogram model. An internal validation was conducted in 225 consecutive patients. Performance and clinical benefit of the model were evaluated using receiver operating characteristic curves and decision curve analysis (DCA), respectively.

RESULTS

Age, cholelithiasis, carcinoembryonic antigen, polyp size, and sessile shape were confirmed as independent predictors of GBP neoplastic potential in the training group. Compared with five other proposed prediction methods, the established nomogram model presented better discrimination of neoplastic GBPs in the training cohort (area under the curve [AUC]: 0.846) and the validation cohort (AUC: 0.835). DCA demonstrated that the greatest clinical benefit was provided by the nomogram compared with the other five methods.

CONCLUSIONS

Our developed preoperative nomogram model can successfully be used to evaluate the neoplastic potential of GBPs based on simple clinical variables that maybe useful for clinical decision-making.

Prevalence of Empyema or Mucocele or Other Histological Diagnoses in Patients Undergoing Cholecystectomy With Diagnosis of Chronic Cholecystitis

Background

Chronic cholecystitis is inflammation of the gall bladder usually caused by stones. The aim was to find out the prevalence of mucocele and empyema in chronic cholecystitis using cholecystectomy findings and histopathological reports.

Methodology

This was a cross-sectional observational study conducted in Surgical Ward 1, Jinnah Postgraduate Medical Center, Karachi from December 2019 to December 2021 for two years. Patients above 12 years of age diagnosed with chronic cholecystitis with cholelithiasis on clinical examination and investigations were included. Patients who were diagnosed with acute cholecystitis, mucocele, or empyema on clinical examination and ultrasonography were excluded from the study. Laparoscopic cholecystectomy was done and operative findings were noted. Gall bladder specimens were examined for mucocele and empyema and were sent for histopathology. Results were recorded and analyzed.

Results

There were 241 patients diagnosed with chronic cholecystitis with cholelithiasis on clinical examination and investigations. On examination, tenderness in the right hypochondrium was absent in all patients. Chronic cholecystitis was proved on histopathology in 231 patients (95.85%). Other findings diagnosed on peroperative findings and histopathology reports were strawberry gall bladder (2.41%), empyema (0.83%), mucocele (0.41%), and polyp (0.41%). Two hundred eight patients were female (86.31%), 33 were male(13.69%). The male to female ratio was 1:6.43. The average age was 31 years.

Conclusion

Inflammation and fibrosis of the gallbladder around Calot’s triangle increase the chances of vascular and common bile duct injury. In such cases, cholecystectomy can become difficult. It was concluded that empyema, mucocele, and strawberry gall bladder could be found in chronic cholecystitis, and cholecystectomy becomes difficult in such cases.

Lymphoid hyperplasia with a polyp form of the gallbladder macroscopically mimicking carcinoma

Lymphoid hyperplasia is a type of tumor-like hyperplasia of lymphoid tissue. There have been few reports on lymphoid hyperplasia of the gallbladder. Here, we report a case of lymphoid hyperplasia with a polyp form of the gallbladder macroscopically mimicking carcinoma. Liver dysfunction was diagnosed in a 75-year-old woman who presented with a gallbladder mass measuring 20 mm during an annual health checkup. Antibody tests for infectious diseases were positive for anti-HBs and anti-HBc antibodies. Accordingly, a laparoscopic cholecystectomy was performed. Macroscopically, the mass was a papillary/sessile tumor (29 × 25 mm) located in the fundus of the gallbladder. Histologically, the tumor was accompanied by an erosion on a portion of the surface layer, while the remaining epithelium showed regenerative changes and mild hyperplasia. No atypia was observed in the constituent epithelium. Hyperplasia of the polarized lymphoid follicles was observed in the interstitium, and tingible body macrophages were scattered in the germinal center. Immuno-histologically, the germinal center showed CD20 positivity, weak CD10 positivity, Bcl-2 negativity, and a high Ki-67 index (MIB-1). These findings suggested that the proliferating lymphoid follicles were reactive rather than neoplastic. Therefore, we diagnosed the patient with lymphoid hyperplasia of the gallbladder and chronic cholecystitis.

Dysplasia and carcinoma of the gallbladder: pathological evaluation, sampling, differential diagnosis and clinical implications

Pathological evaluation of gallbladder neoplasia remains a challenge. A significant proportion of cases presents as clinically and grossly inapparent lesions, and grossing protocols are not well established. Among epithelial alterations, pseudo-pyloric gland metaplasia is ubiquitous and of no apparent consequence, whereas goblet cell metaplasia and a foveolar change in surface cells require closer attention. Low-grade dysplasia is difficult to objectively define and appears to be clinically inconsequential by itself; however, extra sampling is required to exclude the possibility of accompanying more significant lesions. For high-grade dysplasia ('high-grade BilIN', also known as 'carcinoma in situ'), a complete sampling is necessary to rule out invasion. Designating in-situ or minimally invasive carcinomas limited to muscularis or above as early gallbladder carcinoma (EGBC) helps to alleviate the major geographical differences (West/East) in the criteria for 'invasiveness' to assign a case to pTis or pT1. Total sampling is crucial in proper diagnosis of such cases. A subset of invasive GBCs (5-10%) arise from the intracholecystic neoplasm (ICN, 'adenoma-carcinoma sequence') category. Approximately two-thirds of ICNs have invasive carcinoma. However, this propensity differs by subtype. True 'pyloric gland adenomas' (> 1 cm) are uncommon and scarcely associated with invasive carcinoma. A distinct subtype of ICN composed of tubular, non-mucinous MUC6⁺ glands [intracholecystic tubular non-mucinous neoplasm (ICTN)] forms a localised pedunculated polyp. Although it is morphologically complex and high-grade, it appears to be invasion-resistant. Some of the invasive carcinoma types in the gallbladder have been better characterised recently with adenosquamous, neuroendocrine, poorly cohesive and mucinous carcinomas often being more advanced and aggressive.

[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.

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.

Gallbladder polyps: Correlation of size and clinicopathologic characteristics based on updated definitions

BACKGROUND

Different perspectives exist regarding the clinicopathologic characteristics, biology and management of gallbladder polyps. Size is often used as the surrogate evidence of polyp behavior and size of ≥1cm is widely used as cholecystectomy indication. Most studies on this issue are based on the pathologic correlation of polyps clinically selected for resection, whereas, the data regarding the nature of polypoid lesions from pathology perspective -regardless of the cholecystectomy indication- is highly limited.

METHODS

In this study, 4231 gallbladders -606 of which had gallbladder carcinoma- were reviewed carefully pathologically by the authors for polyps (defined as ≥2 mm). Separately, the cases that were diagnosed as "gallbladder polyps" in the surgical pathology databases were retrieved.

RESULTS

643 polyps identified accordingly were re-evaluated histopathologically. Mean age of all patients was 55 years (range: 20-94); mean polyp size was 9 mm. Among these 643 polyps, 223 (34.6%) were neoplastic: I. Non-neoplastic polyps (n = 420; 65.4%) were smaller (mean: 4.1 mm), occurred in younger patients (mean: 52 years). This group consisted of fibromyoglandular polyps (n = 196) per the updated classification, cholesterol polyps (n = 166), polypoid pyloric gland metaplasia (n = 41) and inflammatory polyps (n = 17). II. Neoplastic polyps were larger (mean: 21 mm), detected in older patients (mean: 61 years) and consisted of intra-cholecystic neoplasms (WHO's "adenomas" and "intracholecystic papillary neoplasms", ≥1 cm; n = 120), their "incipient" version (<1 cm) (n = 44), polypoid invasive carcinomas (n = 26) and non-neoplastic polyps with incidental dysplastic changes (n = 33). In terms of size cut-off correlations, overall, only 27% of polyps were ≥1 cm, 90% of which were neoplastic. All (except for one) ≥2 cm were neoplastic. However, 14% of polyps <1 cm were also neoplastic. Positive predictive value of ≥1 cm cut-off -which is widely used for cholecystectomy indication-, was 94.3% and negative predictive value was 85%.

CONCLUSIONS

Approximately a third of polypoid lesions in the cholecystectomies (regardless of the indication) prove to be neoplastic. The vast majority of (90%) of polyps ≥1 cm and virtually all of those ≥2 cm are neoplastic confirming the current impression that polyps ≥1 cm ought to be removed. However, this study also illustrates that 30% of the neoplastic polyps are <1 cm and therefore small polyps should also be closely watched, especially in older patients.

Reabsorption of bile acids regulated by FXR-OATP1A2 is the main factor for the formation of cholesterol gallstone

The purpose of this study was to demonstrate the aberrant metabolism of bile acids in patients with cholesterol gallstone and explore for its underlying mechanisms. The composition of bile acids collected from the patients with cholelithiasis and the control individuals was analyzed by LC-MS. The expression of genes regulating the metabolism of bile acids was quantitatively determined by real-time PCR or Western blot analysis. Cholesterol saturation index of patients with gallstone was significantly higher than that of the controls. The concentrations of taurodeoxycholic acid and taurolithocholic acid in the bile of patients were significantly higher than that of the controls. When compared with the controls, it was remarkable in the patients that the mRNA expression of farnesoid X receptor (FXR) was lower, whereas that of organic anion transporting polypeptide (OATP1A2) was higher. However, the expressions of both mRNA and protein of cytochrome P-450 family 8 subfamily B member 1 (CYP8B1) did not differ between the patients and the controls. Although the protein level of CYP8B1 was significantly lower in the subjects with single nucleotide polymorphism (SNP) rs3732860(G), the composition of bile acids and the ratio of CA to CDCA remained unaltered in the patients with different SNP genotype of CYP8B1. In conclusion, the axis of FXR-OATP1A2 that physiologically regulated the reabsorption of bile acids might play an important role in the composition of bile acids and the development of gallstone. CYP8B1 gene was irrelevant to the altered composition of bile acids in patients with gallstone.NEW & NOTEWORTHY For the first time, our results indicate that the axis of farnesoid X receptor-organic anion transporter polypeptide 1A2 that physiologically regulates the reabsorption of bile acids might play an important role in the regulation of the composition of bile acids and make contribution to the development of cholelithiasis.

Intracholecystic tubular non-mucinous neoplasm (ICTN) of the gallbladder: a clinicopathologically distinct, invasion-resistant entity

Preinvasive tumor-forming gallbladder neoplasms that are composed of small, non-mucinous tubules with complex architecture remain a poorly characterized group. Here, we evaluated the clinicopathological characteristics of this entity. Twenty-eight examples were analyzed. Tumors were invariably pedunculated polyps with thin stalks, often presented as loosely attached intraluminal nodules, with cauliflower architecture (akin to cholesterol polyps) comprised of compact, back-to-back acinar-like, small tubular units with minimal/no cytoplasm showing variable complexity, creating a picture distinct from the other tubular type dysplasia in the gallbladder. Their limited stroma showed distinctive amorphous amyloid-like hyalinization (39%). While some had round nuclei with single prominent nucleoli, others exhibited slightly more elongated nuclei with washed out chromatin reminiscent of papillary thyroid carcinoma. Squamoid/meningothelial-like morules (71%) and subtle neuroendocrine cell clusters (39%) were frequent. The level of cytoarchitectural atypia qualified as high-grade dysplasia (HGD) in all cases, but none were invasive. The background mucosa showed no dysplasia, but cholesterolosis. The majority (n = 8/12) showed diffuse MUC6 expression and lacked MUC5AC expression. Based on these observations, 635 gallbladder carcinomas were re-analyzed for residual/adjacent lesions with entity-defining characteristics disclosed here, and none could be identified. Preinvasive tubular non-mucinous neoplasm of the gallbladder, which we propose to classify as intracholecystic tubular non-mucinous neoplasm, is a clinicopathologically discrete entity, which tends to occur in uninjured gallbladders and in association with cholesterol polyps. By being tubular, non-mucinous and MUC6-positive, it is akin to intraductal tubulopapillary neoplasms of pancreatobiliary tract, but it is also different in many other aspects. Although their cytoarchitectural complexity warrants an HGD/carcinoma classification, they do not show invasion and their distinct characteristics warrant their separate classification.