Gallbladder polypoid lesions, also known as gallbladder augmentation lesions, is a collective term for limited augmentation-like lesions of the gallbladder mucosa. It is classified by pathology: gallbladder cancer, gallbladder adenocarcinoma, gallbladder adenomyosis, and cholesterol polyps. Clinically, there are three categories: cholesterol polyps, benign non-cholesterol polyp-like lesions, and polyp-type early gallbladder cancer.
1.Cholesterol polyp: The pathogenesis is due to the dysfunction of cholesterol lipid metabolism, resulting in a large amount of cholesterol deposited in the intrinsic layer of the gallbladder wall, which rises and protrudes into the gallbladder cavity and covers the normal mucosal epithelium, forming cholesterol polyp. Ultrasound shows that most of the polyps are multiple, less than 10 in diameter, often located at the base of the gallbladder, with strong echogenicity and a large pendulum with a small tip dangling in the gallbladder cavity when adjusted for body position. In case of extensive cholesterol mucosal deposition, the gallbladder wall is thickened due to fibrous tissue hyperplasia and adheres closely to surrounding organs, making separation difficult.
Most patients with cholesterol polyps have no clinical symptoms and the gallbladder functions well, so they only need regular follow-up inspections. No reports of cancer have been found so far.
2, benign non-cholesterol polypoid lesions: these lesions account for about 36% of the total and include the following.
Adenomas, derived from the proliferation of epithelial components, are masses formed due to adenomatous hyperplasia of the gallbladder mucosa. It is more common and is characterized mostly by a tipped, solitary, papillary shape. The histological classification is: papilloma, ductal adenoma, and mixed adenoma. ultrasound shows: all are moderately echogenic, with unsmooth margins, wide tips, solitary, and greater than 10 in diameter, mostly at the base of the gallbladder. Adenomas have obvious malignant potential and are recognized as precancerous lesions. The process is: adenomatous hyperplasia → moderate to severe adenomatous heterogeneous hyperplasia → carcinoma, with a cancer rate of about 10%. Recent studies have shown that the occurrence of adenoma and cancer of gallbladder is related to the long-term stimulation and damage of gallbladder mucosa by stones and chronic inflammation, resulting in heterogeneous proliferation of epithelial cells. The possibility of cancer should be highly suspected when ultrasound shows the following conditions.
(1) Diameter greater than 10.
(2) Solitary.
(3) Located in the neck of gallbladder.
(4) Low to moderate intensity echogenicity.
(5) accompanied by gallbladder stones. Once cancer is suspected, radical cholecystectomy should be performed as soon as possible.
The pathogenesis of adenomyolipoma, also known as adenomyomatosis of the gallbladder, is unclear. RAS). The pathogenesis of RAS is now widely believed to be the result of increased mucosal hyperplasia of the gallbladder, thickening of the gallbladder wall due to muscle hyperplasia, abnormal hyperplasia of nerve fibers in the gallbladder wall, and incomplete embryonic gallbladder budding. Ro-Archis sinuses can reach the plasma membrane surface and are numerous, often with bile stagnation and secondary inflammation forming stones and embedding them. The lesions are classified into the following pathological types according to their location and stage of development: diffuse, segmental, and limited.
(1) Diffuse type: The lesion has epithelial and muscular hyperplasia from the neck to the base, (RAS) involving the whole gallbladder. The cholangiogram shows irregular thickening of the gallbladder wall with many bead-like or lace-like translucent dots around it. （The ultrasound shows the corresponding echogenic, hypoechoic or strong echogenic shadow in multi-axis dynamic view, while the CT clearly shows granular or linear shadow. As cholesterol deposition, adenomyosis and neuroma often coexist, some cases may present with concentrated gallbladder function, hyper-emptying function, manifesting as persistent pain, dyspepsia and other clinical symptoms, some cases may also be combined with stones, chronic cholecystitis, thickening of the cyst wall and gradual atrophy and loss of function.
(2) Segmental type: Initially, the affected cyst wall is circumferentially narrowed, with a width not exceeding 3. At this time, it is also called circumferential glandular hyperplasia, which usually occurs at the site of congenital gallbladder septum and extends to the surrounding gallbladder wall. Cholangiography: 1-2 circumferential strictures in the gallbladder, dividing the gallbladder into 2-3 connected cavities and showing RAS, which can be located between the cystic duct and the funnel, between the funnel and the intermediate part, and between the intermediate part and the base, depending on the site of the stricture. In the progressive stage, the lesion is still confined to a section of the cystic wall, but the extent is larger, and the cystic wall at the lesion is thickened and narrowed with typical formation of RAS, which can be divided into proximal type, located at the funnel part, distal type, located at the distal base, intermediate type, located at the body of the gallbladder, and intermediate distal type, which is more common, with significant distal thickening and complete separation of the lumen when the gallbladder contracts.
(3) Restricted type: the lesion is located at the base of the gallbladder, but the hyperplasia is not only at the base, divided into three stages, the first stage of hyperplasia is outside the septum and poorly developed, the second stage grows significantly, and the third stage of hyperplasia completely closes the channel and shows a restricted papillary mass, the imaging shows: the RAS is connected to the gallbladder lumen and shows filling defect or crater change.
Adenomyoma was previously considered to have no propensity for malignancy, but studies in recent years have shown that it still has the potential for carcinoma, especially glioma. mc to affirm it as a precancerous lesion.
Inflammatory polyps, granulomas caused by direct inflammation, are divided into those without epithelial component and those with epithelial component, with medium quality, single or multiple broad-based nodules, about 5 in diameter, with obvious inflammatory changes in the surrounding cystic wall. The pathological features are mainly mesenchymal cell infiltration, and no cancer has been reported.
Adenomatous hyperplasia, also called hyperplastic polyp, is non-tipped, solitary or multiple, with a diameter of about 5. The pathology is characterized by surface hyperplasia, similar to intestinal epithelial metaplasia, with visible smooth muscle bundles and cupped cells.
Other rare lesions: smooth muscle tumor, lipoma, fibroma, hemangioma, neurofibroma, fibrolipoma, fibro-yellow granulomatosis, hepatopancreatic tissue heterogeneity, etc.
3.Polypoid early gallbladder cancer: it accounts for about 10% of gallbladder polypoid lesions and is divided into papillary type and nodular type. Generally, the diameter does not exceed 20, and adenocarcinoma is more common in about 85%. The cause of its development is generally considered to be related to the long-term stimulation caused by chronic infection of gallbladder stones. About 80% of gallbladder cancer patients are accompanied by gallbladder stones, so gallbladder resection should be performed as early as possible for patients with gallstone disease, especially for elderly patients with obvious clinical symptoms.
When benign polyp-like lesions of gallbladder affect the function of gallbladder, the clinical symptoms of patients are often similar to those of cholelithiasis, and most of them are accompanied by chronic inflammation of gallbladder, which are often indications for LC surgery.
For malignant polyp-like lesions of gallbladder, preoperative ultrasound examination is very important, and the endoscopic ultrasound developed in recent years is also very helpful for the diagnosis of gallbladder cancer. When the lesion is larger than 12 mm, we should highly suspect the possibility of malignancy and perform open radical cholecystectomy to remove the loose connective tissue above and below the gallbladder duct together with the fibrofatty tissue in the liver bed.