Polyp of gallbladder (polyp of gallbladder) is a type of lesion in which the wall of the gallbladder bulges into the cystic cavity in a polyp-like fashion. It is also known as polypoid lesion of gallbladder (PLG). Polypoid lesions of gallbladder can be classified as benign or malignant lesions, but non-neoplastic lesions are more common. It is generally believed that polypoid lesions of gallbladder with a diameter of 15 mm or more are almost all malignant neoplastic lesions, so polypoid lesions of gallbladder have been paid more attention in recent years.
Pathogenesis
The etiology of gallbladder polyp-like lesions is still unclear, but it is generally believed that the occurrence of the disease is closely related to chronic inflammation, of which inflammatory polyps and adenomatous hyperplasia are both inflammatory reactive lesions, and cholesterol polyps are the result of systemic lipid metabolism disorders and local inflammatory response of the gallbladder.
Pathogenesis
PLG is a group of biliary diseases with the same manifestations but with many different pathological states. The pathology is classified into two categories: non-neoplastic lesions and neoplastic lesions, the latter being subdivided into benign and malignant.
1.Non-neoplastic PLG
(1) Cholesterol polyps.
(2) Inflammatory polyps: they are caused by chronic inflammatory stimulation and can be solitary, or multiple, generally 3-5 mm in size, with thick or inconspicuous tips, similar or slightly reddish in color to the adjacent mucosa, and single or multiple broad-based nodules. Histology showed focal glandular epithelial hyperplasia with vascular connective tissue mesenchyme and marked inflammatory cell inflammatory polyps, granulomas due to inflammatory stimulation, and marked inflammation of the gallbladder wall surrounding the polyps. No carcinogenesis has been reported, but from the study of carcinogenesis of gallbladder cancer combined with gallstones, it is believed that bacterial chronic cholecystitis may be one of the factors, so the inflammatory polyps cannot be relaxedly observed.
(3) Adenomatous hyperplasia and adenomyoma: Adenomatous hyperplasia is a kind of hypertrophic lesion of gallbladder wall caused by the proliferation of gallbladder epithelium and smooth muscle, which is divided into 3 types.
①limited type: cone cap-shaped thickening at the base of the gallbladder.
②Segmental type: local thickening of the cystic wall into the lumen to form a “triangular sign”, diffuse centripetal thickening, uneven inner wall, narrowing of the lumen, sometimes accompanied by stones, lipid meal test shows hypercontraction of the gallbladder.
(3) Extensive type: Adenomatous hyperplasia and adenomyomatosis are both proliferative lesions that are neither inflammatory nor neoplastic. The former are soft yellow warts, about 5 mm in diameter, solitary or multiple. They consist of abundant connective tissue containing smooth muscle bundles and cupped cells, with surface epithelial hyperplasia and intestinal metaplasia. The latter consists of localized changes in the mucosal epithelium, myofibrillar hyperplasia and limited adenomyomatosis, also known as adenomyomatosis. Both of these lesions may be cancerous.
2.Neoplastic PLG?Among the neoplastic lesions, benign ones are mainly adenoma, while malignant ones are mainly gallbladder cancer.
(1) Adenoma: Adenomas are mostly single, tipped polyps. The incidence of adenoma is very low, and although it has the possibility of cancer, it does not pose a clinical threat.
(2) Benign mesenchymal tissue tumors: Benign mesenchymal tissue tumors are benign tumors of the gallbladder that originate from supporting tissues. They mainly include fibroma, smooth muscle tumor, and hemangioma.
Symptoms and signs
The vast majority of patients with CPs have no clinical symptoms and have good gallbladder function.
Examination methods
1.B ultrasound examination is flexible, accurate, non-invasive, repeatable, inexpensive and easily accepted by many patients, and can accurately show the size, location, number and cystic wall of polyps.
2.Three-dimensional ultrasound imaging
3.Endoscopic ultrasonography (endoscopic ultrasonography, EUS)
4.CT simulation endoscopy (computed tomographic virtual endoscopy, CTVE)
Disease diagnosis
Color Doppler ultrasound is an important differentiating feature of primary gallbladder cancer from benign masses and metastatic cancers by showing high velocity arterial blood flow signal within the mass and gallbladder wall. For example, blood flow in cholesterol polyps is linear, <500px/s, while blood flow in gallbladder cancer is mostly dendritic, with flow velocity >500px/s. The smaller the RI, the more malignant it tends to be, but it is sometimes not sensitive to early gallbladder cancer masses that are too small (<3mm), and in addition, it has an important relationship with the operator's technical level.
Treatment
The indications for surgery are controversial. Therefore, most people advocate PLGs ≥10 mm in diameter as an indication for surgery, and caution must be maintained for those <10 mm. Therefore, it is considered that a single lesion >60 years old, with coexisting gallstones, and >10 mm should be cholecystectomized even if asymptomatic.
The six tumor risk factors of Deng Shaoqing’s comprehensive PLG are: solitary, >10 mm, broad-based or thick tip, growing lesion, age >50 years, and coexisting stones. However, it is also emphasized that vigilance should not be relaxed for <10 mm and regular follow-up is necessary.
Complications
Polypoid gallbladder cancer accounts for 9% to 12% of cases, and about 50% are associated with gallstones
Prevention
Since the etiology of gallbladder polyp lesions is not clear, it is thought to be related to the chronic inflammatory response to gallbladder inflammation or gallbladder stones. Therefore, the key to preventing gallbladder polyps is to actively treat the disease causing chronic inflammation of the gallbladder.
Prognosis
For those who have obvious symptoms that affect work and life, combined with chronic cholecystitis and stones; polyps with solitary, diameter >10mm, large base or tipped in the neck of gallbladder are indications for cholecystectomy. However, due to the difficulty of preoperative diagnosis of this disease, patients often have a fear of cancer, and there is a tendency to expand the surgery due to the idea of preventing malignant changes.