Gall bladder polyps

Laparoscopic cholecystectomy has largely replaced the open technique since the 1990s (Hassler 2022).

A gallbladder polyp is a benign tumor of the gallbladder (Herold 2022) that is an elevation of the gallbladder wall that extends into the lumen (Wiles 2017).

Gallbladder polyps are divided into pseudopolyps and true polyps.

- 1. pseudopolyps:

Pseudopolyps are distinct than true polyps with 70%. They occur predominantly as cholesterol polyps resp. Cholesterol pseudopolyps occur. They also include focal adenomyomatosis and inflammatory pseudopolyps. Pseudopolyps do not have malignant potential (Wiles 2017).

- 2. true gallbladder polyps:

True gallbladder polyps include adenomas, carcinomas, and metastases (Cocco 2021).

Adenomas account for approximately 10% of all gallbladder polyps (Cocco 2021). Metastases are largely from malignant melanoma, gastric carcinoma, renal cell car cinoma or hepatocellular carcinoma (Cocco 2021).

The prevalence of gallbladder polyps is between 1 - 6 %, in Germany it is 5 % (Gutt 2018). Men are significantly more affected than women (Kasper 2015).

According to a single study by Aldouri et al. from 2009, the prevalence of malignancy in gallbladder polyps is significantly higher in Indian ethnicity at 5.5% compared to the general population at 0.8%. Further studies are warranted here (Wiles 2017).

Cholesterol polyps, the most common type of gallbladder polyp, result from localized cholesterol deposition in the form of lipid-storing macrophages (cholesteatosis) in the area of the gallbladder wall (Lenzen 2015).

An adenoma-carcinoma sequence has been described for adenomas, the most common benign neoplastic gallbladder polyps with a tendency to degenerate (Lenzen 2015).

In adenomyomatosis, proliferation of the gallbladder epithelium with invagination by the muscularis is seen in the fundus or diffusely distributed. In this case, there is often additional cholecystolithiasis. It is currently unclear whether there is an increased risk of gallbladder carcinoma (Lenzen 2015).

Gallbladder polyps are almost always diagnosed incidentally during abdominal sonography (Herold 2022) or during analysis of a gallbladder specimen (Wiles 2017).

Endosonography is subsequently used for accurate diagnosis, as polyps can be detected more precisely with this than with abdominal sonography (80 - 97 % vs. 52 - 76 %). In addition, polyps > 5 mm can be better differentiated from gallbladder carcinoma by endosonography (Gutt 2018).

- Gallbladder carcinoma:

Sonographically, this shows a distinct infiltrating mass (Wiles 2017).

- Gallbladder concrements (Wiles 2017):

Sonic shadow and bright stone reflex can be visualized sonographically (Birnbaum 2013).

- Cholesterol polyps:

The presence of multiple polyps argues against adenoma and more for the presence of cholesterol polyps (Gutt 2018).

Very rarely, the following may occur:

- acute pancreatitis

- acute cholecystitis (Lenzen 2015).

Provided the gallbladder polyp diameter is < 10 mm, few signs of change have been noted within a 5-year period (Kasper 2015).

Beyond that, however, there is an increased risk of carcinoma of 50% (Gutt 2018) and cholecystectomy is therefore advised (Herold 2022).

The goal of therapy for gallbladder polyps is to prevent the development of gallbladder carcinoma (Lenzen 2015).

When gallbladder polyps occur, cholecystectomy is required in certain constellations. A 2017 expert consensus recommendation with three Delphi rounds serves as a guide for gallbladder polyp therapy (Wiles 2017)

Should the gallbladder polyps

- Have a diameter greater than ≥ 1 cm (Herold 2022) and be symptomatic

Or

- Asymptomatic in patients > 50 years of age.

Or

- Present with growth on sonographic inspection

Or

- a cholecystolithiasis is detectable (Kasper 2015)

Cholecystectomy is recommended (because of the increased risk of carcinoma) (Herold 2022).

Cholecystectomy should be planned as an open cholecystectomy in patients with a polyp > 18 - 20 mm, as there is a significant risk of malignancy in this case (Gutt 2018).

Unless cholecystectomy is required according to the above criteria, risk factors for malignancy should be determined. These include:

- Age > 50 years

- Indian ethnicity

- history of primary sclerosing cholangitis (PSC)

- focal wall thickening of the gallbladder > 4 mm with a sitting polyp (Wiles 2017).

In patients with these risk factors, the indication for cholecystectomy shifts from 10 mm - diameter to 6 mm (Wiles 2017).

If cholecystectomy cannot be performed because of, for example, comorbidities, symptoms that cannot be clearly attributed to the gallbladder, etc., further monitoring of the patient is indicated. This should then be decided on a case-by-case basis (Wiles 2017).

Control examinations

- 1. in the following patient groups:

- No risk factors for malignancy and gallbladder polyps < 10 mm in diameter.

- risk factors for malignancy and gallbladder polyps < 5 mm diameter

sonographic control examinations regarding size growth should be performed initially after 6 months, then annually for a total of 5 years (Gutt 2018)

- 2. in patient groups:

- Without risk factors for malignancy and a gallbladder polyp < 5 mm in diameter.

sonographic control examinations are recommended with regard to size growth after 1 year, 3 years and 5 years (Wiles 2017).

If the polyp grows in size by 2 mm or more, the patient should undergo cholecystectomy. If the polyp is no longer detectable during the control examinations, further controls are unnecessary (Wiles 2017).

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