Version July 2025
INTRODUCTION —
Gallbladder polyps are outgrowths of the gallbladder mucosal wall. They are usually found incidentally on ultrasound or after cholecystectomy but can occasionally lead to symptoms similar to those caused by gallbladder stones. Most polyps are not neoplastic but are hyperplastic or represent lipid deposits (cholesterolosis). With the widespread use of abdominal ultrasound, polypoid lesions of the gallbladder are increasingly detected. However, initial imaging cannot exclude the possibility of gallbladder carcinoma or premalignant adenomas. This topic will review the classification, clinical findings, diagnosis, and management of gallbladder polyps, cholesterolosis, and adenomyomatosis. Other gallbladder conditions are discussed separately:
●Gallstones – (See "Approach to the management of gallstones".)
●Acute cholecystitis – (See "Acute calculous cholecystitis: Clinical features and diagnosis" and "Treatment of acute calculous cholecystitis".)
●Gallbladder cancer – (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer" and "Surgical management of gallbladder cancer".)
CLASSIFICATION —
A gallbladder polyp is defined as a sessile or pedunculated protrusion of the gallbladder mucosa into the lumen [1]. Polyps are categorized as neoplastic or non-neoplastic. (See 'Neoplastic polyps' below and 'Non-neoplastic polyps' below.)
Neoplastic polyps — Neoplastic lesions of the gallbladder include:
●Adenomas – A gallbladder adenoma is an abnormal growth that forms on the gallbladder lining. Adenomatous polyps are the most common benign neoplastic lesions of the gallbladder. Adenomas are considered premalignant and are epithelial tumors composed of cells resembling biliary tract epithelium. These lesions are classified based on histology as papillary or non-papillary. An alternative classification system has been proposed in which adenomas are categorized as tubular, papillary (villous), or mixed [2]. (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer", section on 'Histology and molecular pathogenesis'.)
●Other benign neoplasms – Other benign neoplasms of the gallbladder such as fibromas, lipomas, and leiomyomas, are rare. The natural history of these polyp types is not well defined but is probably similar to their counterparts in other regions of the gastrointestinal tract.
●Adenocarcinoma – Most malignant gallbladder polyps are adenocarcinomas. Gallbladder adenocarcinomas are more common than gallbladder adenomas [3]. (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer".)
Other malignant tumors such as squamous cell carcinoma, mucinous cystadenoma, and adenoacanthoma of the gallbladder are rare.
Non-neoplastic polyps — These are benign lesions with no malignant potential. Some studies have referred to such polyps as pseudopolyps; however, we avoid this term because it does not describe their pathology. Nonneoplastic polyps include [4,5]
(see 'Other benign gallbladder lesions' below):
●Cholesterol polyps – Cholesterol polyps are the most common non-neoplastic polyps and represent a polypoid form of cholesterolosis. In a study including 2290 patients with gallbladder polyps on ultrasound who underwent cholecystectomy, 463 polyps (20 percent) were cholesterol polyps [6].
Cholesterol polyps are usually asymptomatic and diagnosed incidentally on ultrasound. However, their fragile stalk can break off, possibly leading to cholecystitis, obstructive jaundice, or pancreatitis [7].
Cholesterol polyps are usually multiple, homogeneous, and pedunculated polypoid lesions that are more echogenic than the liver parenchyma (image 1). They may or may not contain hyperechoic spots and have a mulberry-like surface. Cholesterol polyps are usually smaller than 1 cm.
●Adenomyoma – In some cases, localized adenomyomatosis can give the appearance of a polyp projecting from the fundus into the lumen. (See 'Adenomyomatosis' below.)
●Inflammatory polyps – Inflammatory polyps may be sessile or pedunculated and are composed of granulation and fibrous tissue with plasma cells and lymphocytes. These polyps are slightly echogenic on ultrasound and usually range in size from 5 to 10 mm in diameter [8].
PREVALENCE —
The true prevalence of gallbladder polyps is uncertain because most are found incidentally. In large cohort studies, gallbladder polyps have been observed in up to 8 percent of gallbladders assessed by transabdominal ultrasound [9,10].
CLINICAL PRESENTATION —
The most common clinical presentation is incidentally finding a gallbladder polyp during radiologic imaging of the abdomen for another indication.
For some patients, gallbladder polyps may be associated with biliary colic, which refers to episodic right upper quadrant and/or epigastric pain. Proposed mechanisms of pain include prolapse of the polyp into the gallbladder neck, which, if it occurs during gallbladder ejection, can lead to biliary-type pain that subsides upon spontaneous reduction. Theoretically, a detached portion of a polyp lying free in the gallbladder lumen may obstruct the cystic duct in much the same way as a gallstone would, leading to biliary colic or cholecystitis [7]. Similarly, the detached portion may also obstruct the common bile duct, leading to obstructive jaundice and pancreatitis, but this has been very rarely reported [11,12]. (See "Clinical manifestations and evaluation of gallstone disease in adults", section on 'Biliary colic' and "Acute calculous cholecystitis: Clinical features and diagnosis" and "Clinical manifestations, diagnosis, and natural history of acute pancreatitis".)
Polyps are identified on transabdominal ultrasound as single or multiple echogenic foci. (See 'Transabdominal ultrasound' below.)
EVALUATION
History and physical examination — We assess patients for risk factors for gallbladder cancer (ie, older patient age, history of primary sclerosing cholangitis). (See 'Risk of malignancy' below and "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer", section on 'Risk factors'.)
Most patients with gallbladder polyps are asymptomatic. When symptoms are present, they are similar to those in patients with biliary colic, cholecystitis, biliary obstruction, or pancreatitis (eg, abdominal pain, jaundice). (See "Clinical manifestations and evaluation of gallstone disease in adults".)
Transabdominal ultrasound — On ultrasound imaging, a gallbladder polyp is defined as an elevation of the gallbladder wall that projects into the gallbladder lumen [1]. Polyps can be easily differentiated from gallstones because they are fixed and do not move when the patient is rolled from one side to another. In addition, unlike gallstones, they do not cast a shadow (image 1 and image 2 and image 3).
Polyps may be sessile or pedunculated. For pedunculated polyps, the stalk is often difficult to visualize with ultrasound, but there is a "ball-on-wall” appearance. Sessile polyp morphology, including focal thickness of the gallbladder wall, is a risk factor for malignancy [13].
Transabdominal ultrasound is regarded as the most useful imaging test to detect gallbladder polyps because it is noninvasive, widely available, and does not use ionizing radiation.
Studies have suggested that transabdominal ultrasound performs well for detecting gallbladder polyps but has low sensitivity for differentiating between neoplastic (ie, adenomas) and non-neoplastic polyps or between adenomas and carcinoma. In a meta-analysis of six studies that included 16,260 individuals, the sensitivity and specificity of transabdominal ultrasound for the detection of gallbladder polyps were 84 and 96 percent, respectively [14]. However, in differentiating neoplastic and non-neoplastic polyps, the sensitivity and specificity were lower; in six studies that included 1078 individuals, the sensitivity was 68 percent and specificity was 79 percent [14].
The following characteristics of gallbladder polyps have been noted on ultrasound [15]:
●Cholesterol polyps – Cholesterol polyps are usually multiple, homogeneous, and pedunculated polypoid lesions that are more echogenic than the liver parenchyma (the stalk is rarely visualized, but gives the appearance of "ball on wall" (image 1). They may or may not contain hyperechoic spots and have a mulberry-like surface. Cholesterol polyps are usually smaller than 1 cm.
●Adenomas – Adenomas are homogeneous, isoechoic with the liver parenchyma, have a smooth surface with internal vascularity on Doppler imaging, and usually do not have a stalk (image 2).
●Adenocarcinomas – Adenocarcinomas are homogeneous or heterogeneous polypoid structures that are usually isoechoic with the liver parenchyma, are vascular on Doppler imaging, and exhibit a mulberry-like surface [15]. Sessile polyp morphology with a wide base and focal thickness of the gallbladder wall of more than 4 mm are risk factors for malignancy [13,15]. Adenocarcinomas are usually larger than 1 cm.
●Adenomyoma – In the localized type, adenomyomatosis can give the appearance of a polyp projecting from the fundus into the lumen. (See 'Adenomyomatosis' below.)
Limited role for advanced or other imaging methods — We do not routinely obtain advanced imaging for patients with suspected benign gallbladder polyps because the use of such imaging is limited by availability, diagnostic accuracy, and/or its invasiveness (eg, endoscopic ultrasound [EUS]) [16-18]. However, we obtain advanced imaging when malignancy is suspected (eg, polyps >20 mm in size, focal gallbladder wall thickening). Additional imaging evaluates the depth of invasion into the gallbladder wall and invasion into the liver. Advanced imaging may be helpful in differentiating benign from malignant lesions and differentiating tumefactive sludge from neoplastic lesions. (See 'Management' below.)
●Contrast-enhanced ultrasound – Contrast-enhanced ultrasound (CEUS) is not widely available and data from large, prospective multicenter studies are lacking [19-21]. Small single-center studies suggested that CEUS may facilitate the detection of gallbladder polyps by helping to distinguish them from mural folds, gallbladder contents, or sludge. CEUS may also help differentiate non-neoplastic from neoplastic polyps and help detect invasion into the liver and metastases. In a meta-analysis of 10 studies including 868 patients, the sensitivity and specificity of CEUS for detecting gallbladder adenomas were 85 and 87 percent, respectively [19]. Color Doppler imaging appears to have higher sensitivity than conventional abdominal ultrasound in diagnosing gallbladder lesions, but it cannot reliably differentiate between benign and malignant lesions due to an overlap in flow velocities, particularly with early T1 lesions [22,23].
●Endoscopic ultrasound – Endoscopic ultrasound (EUS) is an invasive procedure, and data have suggested that the diagnostic accuracy of EUS was not superior to transabdominal ultrasound. In a systematic review of nine studies using transabdominal ultrasound and EUS to differentiate neoplastic from non-neoplastic polyps, there was no statistically significant difference in diagnostic accuracy between transabdominal ultrasound and EUS [14]. In addition, in a systematic review of seven studies using these imaging modalities to differentiate between malignant polyps (ie, carcinomas) and benign (ie, adenomas or non-neoplastic) polyps, there was no significant difference in accuracy between imaging tests [14].
●Computed tomography scan – We do not routinely use abdominal computed tomography (CT) for evaluating gallbladder polyps <10 mm because CT has low sensitivity for detecting polypoid lesions, particularly small cholesterol polyps, which are isodense with bile [16]. Abdominal CT may be used for evaluating ultrasound findings that are suspicious for malignancy, such as abnormal gallbladder wall thickening or mass lesion, and this is discussed separately. (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer", section on 'Diagnostic evaluation'.)
DIAGNOSIS —
Gallbladder polyps are usually discovered incidentally on imaging with transabdominal ultrasound as discussed above. (See 'Evaluation' above.)
The diagnosis of a gallbladder polyp can be made with reasonable confidence based on characteristic imaging findings (ie, single or multiple echogenic foci that originate from the gallbladder wall and project into the lumen). However, imaging cannot unequivocally distinguish malignant from benign polyps.
A definitive diagnosis of gallbladder polyp is established with histologic examination at the time of cholecystectomy, although cholecystectomy is not indicated for managing most small polyps. Histologic evaluation also excludes malignancy. (See 'Management' below.)
DIFFERENTIAL DIAGNOSIS —
The differential diagnosis of gallbladder polyps includes:
●Gallstones – Gallbladder polyps can be differentiated from gallstones on abdominal ultrasound because they are fixed and, unlike gallstones, do not move when the patient is rolled from one side to another and do not cast a shadow (image 3). A gallbladder sludge ball does not cast a shadow and can mimic a gallbladder polyp but tends to be in the dependent part of the gallbladder and moves with changing the patient's position. (See "Clinical manifestations and evaluation of gallstone disease in adults".)
●Gallbladder adenocarcinoma – Adenocarcinoma of the gallbladder appears as a polypoid structure. (See 'Transabdominal ultrasound' above.)
Larger lesions appear as an intraluminal mass that can displace gallstones. Findings suspicious for liver invasion include larger lesions with loss of interface with the liver [24]. (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer" and 'Risk of malignancy' below.)
MANAGEMENT
Symptomatic patients — For patients with gallbladder polyps complicated by biliary symptoms or complications such as cholecystitis or pancreatitis, cholecystectomy is the treatment of choice. In some symptomatic patients, small gallbladder polyps may not be the specific cause of symptoms but may be indicative of underlying inflammation or stone disease that may not have been detected on ultrasound. Most patients with gallbladder polyps and biliary symptoms improve after cholecystectomy (algorithm 1) [6,25]. Randomized clinical trials comparing cholecystectomy to observation are lacking; however, this approach is similar to managing patients with biliary colic related to gallstone disease [26]. (See "Approach to the management of gallstones", section on 'Subsequent management'.)
For patients with nonspecific dyspeptic symptoms in the absence of biliary colic, we use medical management, provided that the patient does not have other indications for cholecystectomy. We use this approach because the pathogenesis of dyspeptic symptoms is uncertain in this setting and cholecystectomy may not relieve the symptoms. We manage such patients symptomatically, similar to other patients with dyspepsia. (See "Laparoscopic cholecystectomy", section on 'Indications' and "Approach to the adult with dyspepsia".)
Asymptomatic patients
Factors that guide decision-making — The management of asymptomatic patients with gallbladder polyps takes into account polyp size, polyp morphology, and the patient's risk factors for gallbladder cancer (eg, age, country from which the patient is from). Much of our approach is based on expert opinion since data from randomized trials are not available to guide practice. (See 'Risk of malignancy' below.)
Larger polyps (≥10 mm) — We refer patients with large gallbladder polyps (≥10 mm) for cholecystectomy given the higher rates of malignancy in such polyps (algorithm 1). (See 'Risk of malignancy' below.)
We also obtain preoperative cross-sectional imaging (eg, CT scan) for evaluation for gallbladder cancer. The management of gallbladder cancer is discussed in detail separately. (See "Surgical management of gallbladder cancer".)
●Polyps >20 mm – Given the high rate of malignancy in gallbladder polyps >20 mm, an extended cholecystectomy with lymph node dissection is indicated [24]. Extended cholecystectomy involves en bloc removal of the gallbladder with a rim of liver of at least 2 cm adjacent to the gallbladder bed. A formal central liver resection (segments IV and V) may be appropriate depending upon the location.
●Polyps 10 to 20 mm – Polyps 10 to 20 mm in diameter should be regarded as possibly malignant. Cancer of this size is usually at an early stage and simple cholecystectomy with full-thickness dissection (removal of the entire connective tissue layers of the gallbladder bed to expose the liver surface) is typically performed [24,27]. (See 'Risk of malignancy' below.)
Smaller polyps (<10 mm)
Patients with risk factors — In addition to gallbladder adenoma(s), certain patient and polyp factors are associated with an increased risk of gallbladder cancer.
These factors include (see 'Natural history' below):
●Patient age >60 years.
●High-risk geography (ie, individuals from East Asia or India) and Native American individuals.
●Sessile polyps (wide base) and >4 mm focal gallbladder wall thickness.
For patients with smaller polyps who have an additional risk factor, management is based on polyp size (algorithm 1) [1]:
●Polyps 6 to 9 mm – For polyps 6 to 9 mm, we refer the patient for cholecystectomy given the increased risk for gallbladder cancer. For patients who are unable or unwilling to undergo cholecystectomy, we perform surveillance ultrasounds every six months for a year and then, if stable in size, annually.
●Polyps ≤5 mm – For polyps ≤5 mm, we obtain transabdominal ultrasound every six months for one year, and if polyp size remains stable, annually thereafter.
Patients without risk factors — We use surveillance imaging for asymptomatic patients with smaller polyps but without other risk factors for gallbladder cancer.
Surveillance intervals are based on polyp size (algorithm 1) (see 'Natural history' below):
●Polyps 6 to 9 mm – For patients with a gallbladder polyp 6 to 9 mm in size, we obtain transabdominal ultrasound every six months for one year, and if polyp size remains stable, annually thereafter. Our approach is based on studies that demonstrated the need for follow-up due to the risk of gallbladder cancer. As an example, in a study of 1027 patients with gallbladder polyps who were followed for more than one year; thirty-three patients (2.1 percent) were diagnosed with neoplastic polyps [28]. The cumulative detection rates of neoplastic polyps were 1.7 percent at one year, 2.8 percent at five years, and 4 percent at eight years. Increase in polyp size was noted in 36 patients (3.5 percent), of which nine (0.8 percent) were neoplastic. Of those nine polyps, six polyps were less than 10 mm in size prior to the start of follow-up [28]. However, data are conflicting and other prospective studies have demonstrated that growth is part of the natural history of gallbladder polyps and that the risk of gallbladder cancer remains low [9]. In addition, some society guidelines discontinue ultrasound surveillance after two years if the polyp has remained stable in size [1].
●Polyps ≤5 mm – For patients with gallbladder polyps ≤5 mm in size, we obtain transabdominal ultrasound at one, three, and five years before discontinuing surveillance, provided that the polyp remains stable in size. Polyps ≤5 mm are usually benign and most frequently represent cholesterol polyps. If the gallbladder polyp disappears during the period of surveillance, which may occur with cholesterol polyps, we discontinue the ultrasound surveillance protocol.
This approach is based on multiple studies suggesting that polyps smaller than 6 mm may develop malignancy over time [9,13,29,30]. However, some society guidelines do not endorse imaging surveillance for polyps ≤5 mm in patients without risk factors for gallbladder malignancy [1].
NATURAL HISTORY
Continued growth or regression — If left in situ, benign neoplastic gallbladder polyps may increase or decrease in size or may resolve. An increase in size by >2 mm on imaging within a two-year period may represent a clinically relevant increase in size that warrants consideration of cholecystectomy. The decision of whether to continue surveillance or perform cholecystectomy is based on the final size of the polyp, the patient's risk factors for gallbladder cancer, patient preferences, and multidisciplinary input [1,9]. An increase of >3 mm in size within one year suggests higher risk for gallbladder cancer and is an indication for cholecystectomy. In a cohort study of over 400 patients with gallbladder polyps who underwent cholecystectomy and had a minimum of two ultrasounds at least six months apart prior to surgery, a polyp growth rate of over 3 mm per year on ultrasound was a risk factor for having neoplastic polyps [31].
Some studies involving surveillance imaging suggested that gallbladder polyps usually grow or remain stable in size. In one study of 35,970 adults with an intact gallbladder on ultrasound, of whom 6359 patients had follow-up testing, the unadjusted cumulative probabilities of polyp growth of at least 2 mm at 10 years were 66 percent in polyps <6 mm and 53 percent in polyps 6 mm to <10 mm [9]. In an earlier systematic review of 43 studies that varied in duration of follow-up from six months to seven years, 10 publications assessed polyp growth rate. On pooling the data, 8 percent (231 of 3015 gallbladder polyps) increased in size, 45 percent (734 of 1627 polyps) remained unchanged in size, 7 percent (111 of 1577 polyps) decreased in size and 8 percent (45 of 591 polyps) disappeared completely [32].
Risk of malignancy — Most gallbladder polyps are benign, although adenomas are regarded as having malignant potential. (See 'Neoplastic polyps' above.)
The risk of gallbladder cancer is related to polyp-specific factors and patient-specific factors:
●Polyp-size – For patients with smaller gallbladder polyps, the overall risk of developing gallbladder cancer appears to be low. However, the risk of having premalignant adenoma or cancer increases with polyp size [6,9,33-37]. In a cohort study of 35,856 adults with gallbladder polyps on ultrasound, 19 patients (0.053 percent) were diagnosed with gallbladder cancer, similar to those without polyps (316 of 586,357 patients [0.054 percent]) [9]. Gallbladder cancer was uncommon in patients with gallbladder polyps, with an overall rate of 11.3 per 100,000 person-years. However, the risk of gallbladder cancer varied based on polyp size, with a risk of 1.3 per 100,000 person-years for polyps smaller than 6 mm and 128.2 per 100,000 person-years for polyps larger than 10 mm. In a retrospective analysis using a nationwide network and registry of histopathology including over 200,000 patients who underwent cholecystectomy, 2085 patients (0.9 percent) had gallbladder polyps [36]. Of these polyps, 56 percent were neoplastic (40 percent adenomas, 60 percent malignant polyps). Neoplastic polyps were larger in size compared with non-neoplastic polyps (18.1 mm versus 7.5 mm). Similarly, in a retrospective study including 686 patients with gallbladder polyps who underwent cholecystectomy, polyp size >1.15 cm was a risk factor for adenomatous histology [34]. In another study including 438 patients with gallbladder polyps who were followed for a mean duration of six years, three patients developed cancer (0.7 percent) [37]. All cancers occurred in patients with polyps ≥10 mm (three of 51 patients, 5.9 percent), whereas no cancers were reported in polyps <10 mm.
In older surgical series, the incidence of gallbladder cancer in surgically resected gallbladders ranged from 43 to 77 percent in polyps larger than 10 mm [38] and was approximately 100 percent in polyps larger than 20 mm [39]. However, the malignancy risk reported in retrospective surgical series has an inherent bias because patients were referred for cholecystectomy mostly for symptoms and larger polyps.
●Polyp morphology – Sessile polyp morphology has been associated with risk of cancer. In a systematic review of 21 studies, sessile polyp morphology was an independent risk factor for malignancy and was associated with a sevenfold increase in risk for gallbladder cancer [13].
●Patient-related factors
•Geographical risk factors – East Asian individuals, Indian individuals, and Native American individuals may be at increased risk for gallbladder cancer [40,41]. In a systematic review of 43 studies, of which 29 were performed in Asia, the risk of malignant gallbladder polyps was noted to be higher in Asia as compared with Europe (14.2 versus 6.2 percent) [32]. (See "Epidemiology, risk factors, clinical features, and diagnosis of gallbladder cancer", section on 'Epidemiology'.)
•Older age – Older age has been associated with increased risk of malignant gallbladder polyps, although the specific age threshold has varied among studies [29,42]. In a systematic review including 12 studies and 5482 gallbladder polyps, age >60 years was associated with an increased risk for malignancy, and this age threshold has been used in society guidelines for risk stratification [1,29].
•Primary sclerosing cholangitis – Gallbladder mass lesions or polyps exhibit a higher risk of malignancy in patients with primary sclerosing cholangitis (PSC). Management of gallbladder polyps in patients with PSC is guided by polyp size, liver synthetic function, risk of perioperative liver decompensation, and risk of hepatobiliary infection. These issues are addressed separately. (See "Primary sclerosing cholangitis in adults: Management".)
●Cholelithiasis – Whether coexisting gallstones increase risk of gallbladder cancer in patients with gallbladder polyps has been uncertain because studies are mixed [28,36,41,43,44]. In addition, some data suggested that gallstones may prevent adequate evaluation of gallbladder polyps [45]. If gallstones are a risk factor, the overall risk appears to be small. For patients with coexisting gallstones, we use an individualized approach based on patient risk factors, comorbidities, and preferences. (See "Approach to the management of gallstones".)
OTHER BENIGN GALLBLADDER LESIONS
Cholesterosis — Cholesterolosis is a benign condition characterized by the accumulation of lipids in the mucosa of the gallbladder wall [46]. It is either diffuse or polypoid. The term cholesterolosis refers to the diffuse type. Cholesterol polyps are the polypoid form of cholesterolosis.
●Prevalence – Cholesterolosis is common; prevalence in older surgical studies varies from 9 to 26 percent [46,47]. As an example, an autopsy series of 1300 cases reported that the prevalence of cholesterolosis was 12 percent [47].
●Pathogenesis – Cholesterolosis results from abnormal deposits of triglycerides, cholesterol precursors, and cholesterol esters in the gallbladder mucosa. The lipid accumulation creates yellow deposits that are generally visible macroscopically. The appearance of the yellow deposits on a background of hyperemic mucosa led to the description of this finding as a "strawberry gallbladder" (picture 1).
The main microscopic feature is the presence of lipid-laden macrophages within elongated villi. Most of the lipid in the cytoplasm of the macrophages is in the form of liquid crystals, which are birefringent under polarized light microscopy, giving the macrophages a characteristic foamy appearance (picture 2).
The hyperplastic villus is filled and distended with these cells, creating small yellow nodules under the epithelium. In about two-thirds of cases, these nodules are less than 1 mm in diameter, which gives the mucosa the coarse and granular appearance that is characteristic of the diffuse or planar type of cholesterolosis. The nodules in the remaining one-third of cases are larger and polypoid in appearance (polypoid form) [47].
In the polypoid form, the deposits give rise to solitary or multiple cholesterol polyps that are attached to the underlying mucosa with a fragile epithelial stalk, the core of which is composed of lipid-filled macrophages. These polyps can break off, leading to complications similar to those caused by small gallstones including biliary pain and obstructive jaundice. (See 'Non-neoplastic polyps' above.)
●Imaging – On ultrasound, cholesterolosis appears as hyperechoic foci on the gallbladder wall, causing a reverberation effect leading to comet-tail artifacts [15].
Adenomyomatosis — Adenomyomatosis is an abnormality of the gallbladder characterized by overgrowth of the mucosa, thickening of the muscle wall, and intramural diverticula.
●Classification – Adenomyomatosis can be categorized macroscopically as:
•Segmental – In segmental adenomyomatosis (also referred to as annular adenomyomatosis), a circumferential ring divides the gallbladder into separate interconnected compartments.
•Localized – In localized adenomyomatosis (also referred to as fundal adenomyomatosis), the cystic structure forms a nodule, usually in the fundus, that projects into the lumen, giving the appearance of a polyp on ultrasound (image 4) [48,49]. (See 'Non-neoplastic polyps' above.)
•Diffuse – Diffuse adenomyomatosis causes thickening and irregularity of the mucosal surface and the muscle layer, leading to cystic-like structures in the gallbladder wall or polypoid projections from the mucosa of the gallbladder. In the early phases, the intramural extension of the epithelium creates tubules and crypts in the lamina propria that accumulate mucous. Fluid-filled mucosal pockets eventually herniate into the wall of the gallbladder and through the muscularis propria, forming cystic structures that are visible on gross inspection as pools of bile in the gallbladder wall (Rokitansky-Aschoff sinuses). The point of herniation may appear sealed due to hypertrophy of the muscularis.
●Prevalence – The prevalence of adenomyomatosis of the gallbladder is low but appears to be higher in females. As an example, in a review of over 10,000 cholecystectomies, adenomyomatosis was found in 103 cases (1 percent) [50]. In another study including 2290 patients with polyps on ultrasound who underwent cholecystectomy, adenomyomatosis was found in 61 patients (2.7 percent) [6].
●Imaging – On ultrasound, adenomyomatosis appears as hypoechoic, usually along with hyperechoic cholesterol crystals or calcifications generating a reverberation effect leading to comet-tail artifacts. In the localized type, the cystic structure, which is usually located in the fundus of the gallbladder, can project into the lumen giving the appearance of a polyp or a mass, sometimes confused with gallbladder cancer [15].
●Risk of cancer – Whether adenomyomatosis increases the risk of gallbladder cancer has been uncertain. If the risk is increased, the magnitude of risk appears to be small [51,52]. However, adenomyomatosis has been associated with more advanced gallbladder cancer, possibly because it may prevent early diagnosis of cancer on imaging. In a series of 97 patients with gallbladder cancer, 25 patients (25 percent) had adenomyomatosis and had increased risk for a more advanced T stage, and for lymph node and distant metastases [53].
Management — Patients with cholesterolosis and adenomyomatosis are usually asymptomatic and no medical therapy is necessary. In addition, we do not perform imaging surveillance or cholecystectomy for the indication of cholesterolosis or adenomyomatosis [48]. Although some patients may have dyspepsia that is possibly related to impaired gallbladder emptying, studies supporting cholecystectomy in this setting are lacking.
SPECIAL POPULATIONS
Patients with primary sclerosing cholangitis — The management of gallbladder polyps in patients with primary sclerosing cholangitis is guided by polyp size, liver synthetic function, risk of biliary infection, and risk of perioperative liver decompensation related to the underlying liver disease. Management of gallbladder polyps in patients with primary sclerosing cholangitis is discussed separately. (See "Primary sclerosing cholangitis in adults: Management".)
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cholecystitis and other gallbladder disorders".)
SUMMARY AND RECOMMENDATIONS
●Background – A gallbladder polyp is defined as a sessile or pedunculated protrusion of the gallbladder mucosa into the lumen. Polyps are categorized as neoplastic or non-neoplastic. The most common benign neoplastic polyp is gallbladder adenoma, whereas most malignant gallbladder polyps are adenocarcinomas. The most common non-neoplastic polyps are cholesterol polyps followed by adenomyomas (localized type) and inflammatory polyps. (See 'Classification' above.)
●Clinical presentation – Gallbladder polyps are usually found incidentally on transabdominal ultrasound or after cholecystectomy, and most patients are asymptomatic. However, a detached portion of a polyp lying free in the gallbladder lumen can obstruct the cystic duct in much the same way a gallstone would, leading to biliary colic (ie, episodic right upper quadrant and/or epigastric pain) cholecystitis or, rarely, pancreatitis and obstructive jaundice. (See 'Clinical presentation' above.)
●Risk of malignancy – The overall risk of developing cancer in a gallbladder polyp appears to be low but increases with polyp size (typically ≥10 mm). Other risk factors for gallbladder cancer include patient age >60 years, sessile polyp morphology including >4 mm focal gallbladder wall thickening, history of primary sclerosing cholangitis, and high-risk geographic location (ie, East Asian individuals, Indian individuals, Native American individuals). (See 'Risk of malignancy' above.)
●Evaluation and diagnosis – Gallbladder polyps are usually discovered incidentally on imaging with transabdominal ultrasound. A suspected diagnosis of gallbladder polyp can be made with reasonable confidence based on characteristic imaging findings (ie, single or multiple echogenic foci that originate from the gallbladder wall and project into the lumen). However, imaging cannot unequivocally distinguish malignant from benign polyps. This is established by histologic examination of the gallbladder after cholecystectomy. (See 'Evaluation' above.)
The evaluation includes obtaining a history to identify risk factors for gallbladder cancer and symptoms of biliary colic.
●Management of symptomatic patients – For patients with biliary symptoms or other complications related to gallbladder polyps (eg, cholecystitis), cholecystectomy is the treatment of choice. This approach is similar to managing patients with biliary colic related to gallstones. (See 'Symptomatic patients' above and "Clinical manifestations and evaluation of gallstone disease in adults".)
●Management of asymptomatic patients – Management of asymptomatic gallbladder polyps is based on polyp size, polyp morphology, and the patient's risk factors for gallbladder cancer (algorithm 1) (see 'Management' above):
•Larger polyps (≥10 mm) – For patients with larger gallbladder polyps (≥10 mm), we suggest cholecystectomy rather than surveillance (Grade 2C). Larger polyps have a higher risk of malignancy. (See 'Risk of malignancy' above.)
•Smaller polyps (<10 mm):
-Patients with risk factors: For patients with smaller polyps who have at least one additional risk factor (eg, age >60 years, high-risk geographic location, sessile polyp morphology including >4 mm focal gallbladder wall thickening), management is based on polyp size.
For patients with polyps 6 to 9 mm and at least one additional risk factor, we suggest cholecystectomy rather than surveillance (Grade 2C). For patients who are unable or unwilling to undergo cholecystectomy, we obtain transabdominal ultrasound every six months for one year, and if polyp size remains stable, annually thereafter.
For patients with polyps ≤5 mm and at least one additional risk factor, we obtain transabdominal ultrasound every six months for one year, and if polyp size remains stable, annually thereafter.
-Patients without risk factors: For patients with polyps 6 to 9 mm, we obtain transabdominal ultrasound every six months for one year, and if polyp size remains stable, annually thereafter.
For patients with polyps ≤5 mm, we obtain transabdominal ultrasound at one, three, and five years before discontinuing surveillance, provided that the polyp remains stable in size.
●Cholesterolosis and adenomyomatosis – Cholesterolosis and adenomyomatosis are non-neoplastic and asymptomatic lesions that are usually discovered incidentally. These conditions do not require imaging surveillance or cholecystectomy. (See 'Other benign gallbladder lesions' above.)
●Patients with primary sclerosing cholangitis – The management of gallbladder polyps in patients with primary sclerosing cholangitis is based on polyp size, liver synthetic function, and risk of perioperative liver decompensation. The management of gallbladder polyps in patients with primary sclerosing cholangitis is discussed separately. (See "Primary sclerosing cholangitis in adults: Management".)
