What Are Gallbladder Polyps?

Overview

The gallbladder is a part of the digestive system, it is a small sac that lies beneath the liver and stores the bile (a fluid produced by the liver to digest the fat in the food consumed). Bile contains bile pigments, bile salts, lipids and cholesterol which are released by the gallbladder through the bile duct into the small intestine where the food is waiting to be digested and it helps to break down the fats. 

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are abnormal growths that appear on the inside lining of the gallbladder. Mostly they are benign (non-cancerous) and can rarely be cancerous. They show no symptoms and are detected by imaging studies. They may be caused by inflammation, excess cholesterol deposit or abnormal cell growth.

A gallbladder polyp that is larger than 10mm is considered to be malignant or more likely to be cancerous. Gallbladder polyps that are larger than 18mm are considered a significant risk of being malignant. A larger gallbladder polyp is treated by surgical removal of the gallbladder (cholecystectomy).

Types of gallbladder polyps

Gallbladder polyps may be broadly grouped into non-neoplastic polyps (do not have the potential to become cancerous) and neoplastic polyps (can become cancerous). Sonographically (imaging technique) identified gallbladder polyps are non-neoplastic polyps, most commonly benign cholesterol polyps or inflammatory-type polyps. Non-neoplastic polyps are usually smaller than 10mm in diameter.¹ Neoplastic polyps are diagnosed mostly after the cholecystectomy, mostly they are referred to as various types of adenomatous polyps or adenomas. Neoplastic polyps are larger (18-21mm) than non-neoplastic polyps. 

The different types of gallbladder polyps are: 

1. Pseudopolyps: 

These are also known as cholesterol polyps, this is due to the benign condition known as cholesterolosis. In this condition, small deposits of cholesterol lipids accumulate and form lumps that attach to the wall of the gallbladder forming polyps. These cholesterol deposits are not related to having high blood cholesterol levels. These are usually harmless but occasionally can cause pain.

2. Adenomyomatosis:

This is an abnormal overgrowth of the gallbladder lining where small cystic space forms lumps and forms cysts in the gallbladder wall. It is believed to be benign and surgeons may recommend gallbladder removal (cholecystectomy) if the lump is larger.

3. Inflammatory polyps:

This is due to chronic inflammation of the gallbladder wall (cholecystitis). The irritation of the gallbladder may be associated with the blocking of the duct by gallstones (biliary colic).

4. Adenomas:

These are benign tumours composed of cells resembling the lining of the biliary tract, the channel that connects the gallbladder to other organs. Adenomas of the gallbladder are uncommon, they may have the potential to develop into gallbladder cancer. They are usually seen in cholecystectomy specimens or during imaging studies. The larger the polyps, the higher the risk of developing cancer.

5. Malignant polyps:

The most common type of cancer that affects the internal organs is adenocarcinoma.

Causes of gallbladder polyps

The exact cause of the formation of gallbladder polyps is unknown, but there are several factors that contribute to the development of the polyp. The most common types of gallbladder polyps are cholesterol polyps and inflammatory polyps, while adenomas or adenomyomatosis are very rare.

Cholesterol polyps:

These are caused by the condition known as cholesterolosis, where high levels of cholesterol accumulation in the inner lining of the gallbladder form polyps. They may occur as individual polyps or form groups of polyps (known as diffused cholesterolosis). Doctors call the diffused cholesterolosis “strawberry gallbladder” as the appearance of the tissue resembles a strawberry when examined under a microscope.

Inflammatory polyps:

Cholecystitis is the inflammation of the gallbladder, caused mostly when the gallstone blocks the tube leading out of the gallbladder. This causes the accumulation of bile and leads to inflammation. Cholecystitis also causes bile duct problems, tumours, serious illness and infections.

Signs and symptoms of gallbladder polyps

Gallbladder polyps commonly cause no symptoms. They are usually diagnosed accidentally when testing or imaging is done for other reasons. The polyp in the cystic duct obstructs the flow of the bile causing inflammation of the gallbladder wall (cholecystitis). This may lead to bile accumulation in the bile duct and cause inflammation of the bile duct (cholangitis) or the pancreas (pancreatitis).

However, if the gallbladder polyp grows it becomes symptomatic. These are the signs and symptoms: 

1. Abdominal pain

Pain or discomfort in the upper right side of the abdomen is the most common symptom. The pain may be dull, intermittent, and may even radiate to the back or to the right shoulder.

2. Nausea and vomiting

Some people might experience nausea and vomiting after having oily or fatty foods.

3. Fever

When the gallbladder polyp gets infected it causes inflammation in the gallbladder wall resulting in fever, chills and persistent abdominal pain.

4. Jaundice

Jaundice is a condition in which the skin, eyes and mucous membrane turn yellow because of the high level of bilirubin. Bilirubin is the yellow pigment present in the bile. Jaundice may occur due to hepatitis, gallstones and tumours. A high bilirubin level indicates a disturbance in converting bilirubin into bile or the bile duct is blocked.

5. Digestive disturbance

Gallbladder polyps that obstruct the flow of bile can cause digestive disturbances such as indigestion, bloating, diarrhoea or constipation.

These symptoms are not only caused by the gallbladder polyp but can also be present in other gallbladder or digestive conditions. So when you notice these symptoms it is advised to consult a medical practitioner for proper diagnosis and appropriate treatment for the condition.

Management and treatment for gallbladder polyps

Most gallbladder polyps do not show any symptoms, but the doctors will recommend observing the polyp from time to time to make sure they are not growing big or too fast or producing new symptoms. Ultrasound will be used to confirm this.^2,3

Surgery is the only known treatment for gallbladder diseases. If the gallbladder polyp is enlarged the doctors will recommend removal of the gallbladder (cholecystectomy) to prevent further complications. A person can live without a gallbladder. There are two types of gallbladder removal surgery, they are:

Laparoscopic cholecystectomy

This is a minimally invasive surgery done with few small incisions (cuts) meaning the surgeon looks inside the body without making a large incision. To do a laparoscopy, a surgeon needs to make a small cut through which they insert a thin tube with a camera, this tube is called a laparoscope. This camera sends images from inside of the body to the monitor which allows the surgeon to see inside and helps to locate the gallbladder. The surgeons make one or two small cuts and insert special surgical tools and remove the gallbladder.⁴

Laparoscopy is also termed as “minimally invasive surgery” or “keyhole surgery”. Surgeons prefer this method because it has fewer complications, faster recovery, less pain and smaller scars. People are able to go home on the same day as their surgery, but sometimes a one-night stay in the hospital is needed. It takes about a week for full recovery.

Open cholecystectomy

An open cholecystectomy requires a large incision under the right rib cage to open up the abdomen. This is required when cancer is highly suspected. The surgeon may have to remove the affected tissues and lymph nodes other than the gallbladder. This is a longer procedure with a longer recovery time. People who undergo this procedure may need to spend 3 days in the hospital and will take up to 4 - 6 weeks for full recovery.

Diagnosis

Gallbladder polyps are often diagnosed accidentally during the transabdominal ultrasound. To know the specifics, further tests are needed.²

• Ultrasonography

Abdominal ultrasound is the best for diagnosing gallbladder polyps, because of the sensitivity and specificity. The polyps can be located, counted, and measured with the help of ultrasound, and also the three layers of the gallbladder wall and any abnormalities can be viewed using ultrasound. This helps to distinguish a cholesterol polyp from an adenoma or adenocarcinoma type polyp, but it is difficult to distinguish the polyp as benign or malignant with only ultrasound.^4,5

• Endoscopic ultrasonography (EUS)

This helps in the diagnosis of gastrointestinal malignancies (gastrointestinal cancer), submucosal lesions of the gastrointestinal tract and abnormalities seen on cross-sectional imaging. Endoscopic ultrasonography is considered better than conventional ultrasound because it can provide high-resolution images of small lesions.

• Computed tomography (CT)

Abdominal CT is incapable of detecting low-density lesions especially when the polyp is smaller than 10mm in diameter, but it is helpful in diagnosing gallbladder carcinoma (cancer).

Risk factors

People who have certain health conditions are prone to develop gallbladder polyps, they are:

• Gallstones - These are a hardened collection (stone-like) of bile materials developed in the gallbladder
• Cholecystitis - This is the redness and swelling of the gallbladder due to accumulation of bile
• Cholangitis - This is the inflammation of the bile duct when the bile duct becomes damaged, bile can back up into the liver and cause liver failure (liver cirrhosis)
• Hepatitis B - This is a virus that infects the liver causing inflammation
• High cholesterol
• Peutz-Jeghers syndrome - This is a genetic disorder in which polyps form in the intestine, and dark coloured spots form on various parts of the body. It has a high risk of developing into cancers
• People who are over 50 years of age

FAQs

How can I prevent gallbladder polyps?

Preventing the occurrence of gallbladder polyps is not completely possible as there are multiple causative factors, but following a certain lifestyle can reduce the risk of polyp formation and growth. They are:

• Maintaining a proper diet
• Regular exercise
• Regular medical check-ups

How common are gallbladder polyps?

Studies suggest that 4% to 7% of adults may develop gallbladder polyps, but only 5% of these can lead to cancer.

When should I see a doctor?

Gallbladder polyps are mostly asymptomatic and are diagnosed during an ultrasound. If the doctor recommends removal of the gallbladder it is better to remove it and be on the safe side.

Summary

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are abnormal growths that appear on the inside lining of the gallbladder. Mostly they are benign (non-cancerous) and can rarely be cancerous (malignant). The exact cause of the gallbladder polyp is unknown, but there are several factors that contribute to the development of the polyp. If the gallbladder polyp is enlarged the doctors will recommend removal of the gallbladder.