Gallbladder polyp

Introduction

Gallbladder Polyps are growths or lesions resembling growths (polypoid lesions) in the wall of the gallbladder. True polyps are abnormal accumulations of mucous membrane tissue that would normally be shed by the body. The main types of polypoid growths of the gall bladder include: cholesterol polyp/cholesterosis, cholesterosis with fibrous dysplasia of gall bladder, adenomyomatosis, hyperplastic cholecystosis and adenocarcinoma.


(The patient is a 52 year old male with "cholelithiasis", intermittant jaundice, recent pancreatitis and gallbladder polyps)

Epidemiology

Polypoid lesions of the gallbladder affect approximately 5% of the adult population. The causes are uncertain, but there is a definite correlation with increasing age and the presence of gallstones (choleolithiasis). Most affected individuals do not have symptoms. The gallbladder polyps are detected during abdominal ultrasonography performed for other reasons.

The incidence of gallbladder polyps is higher among men than women. The overall prevalence among men of Chinese ancestry is 9.5%, higher than other ethnic types.

Pathology

Most small polyps are not cancerous and may remain unchanged for years. However, when small polyps occur with other conditions, such as primary sclerosing cholangitis they are less likely to be benign. Larger polyps are more likely to develop into adenocarcinomas.

Cholesterolosis is characterized by an outgrowth of the mucosal lining of the gallbladder into finger-like projections due to the excessive accumulation of cholesterol and triglycerides within macrophages in the epithelial lining. These cholesterol polyps account for most of the benign gallbladder polyps.

Adenomyomatosis describes a diseased state of the gallbladder in which the gallbladder wall is excessively thick due to proliferation of subsurface cellular layer. It is characterized by deep folds into the muscularis propria. Ultrasonography may reveal the thickened gallbladder wall with intramural diverticula.

Symptoms and Diagnosis

Most polyps do not cause noticeable symptoms. Gallbladder polyps are usually found incidentally when examining the abdomen by ultrasound for other conditions, usually abdominal pain.

Therapy

Most polyps are benign and do not need to be removed. Polyps occurring in people over the age of 50 or larger than 1 cm with co-occurring gallstones may have the gallbladder removed (cholecystectomy}, especially if the polyps are severe or appear malignant. Laproscopic surgery is an option for small or solitary polyps.

Five types of polyps are found in the gallbladder and the 3 most common are nonneoplastic.^[1] Cholesterol polyps account for 60% of all gallbladder polyps; they are usually multiple and pedunculated and range in size from 2-10 mm. These polyps occur as part of focal or generalized cholesterolosis of the gallbladder and are not neoplasms. Occasionally, cholesterol polyps can slough off and cause biliary colic from cystic duct obstruction or acute pancreatitis by blocking the common bile duct.

Adenomyomas (or adenomyomatosis) represent the second most common type of gallbladder polyp. These account for 25% of gallbladder polypoid lesions and are usually solitary, ranging in size from 10-20 mm on average. Adenomyomatosis is usually found at the fundus of the gallbladder. The lesions cause focal thickening of the gallbladder wall. They are associated with branching and dilatation of Rokitansky-Aschoff sinuses and hyperplasia of the muscle layer of the gallbladder wall. On ultrasound or oral cholecystography, these lesions appear as a focal thickening of the gallbladder wall. The dilated and branching Rokitansky-Aschoff sinuses appear as intramural defects rather than polyps projecting into the lumen. The only clinical significance of adenomyomatosis occurs when the disease is segmentally distributed in the gallbladder, leading to a concentric narrowing or constriction of the gallbladder lumen. This type of lesion is associated with an increased incidence of gallbladder cancer, and the gallbladder should be removed surgically.

The best treatment for gallbladder polyps is to surgically remove the gallbladder when adenomas >/= 10 mm are present. The problem is that the majority of lesions of this size that are discovered on ultrasound will be among 1 of the 3 nonneoplastic types of gallbladder polyps. I would still recommend an elective cholecystectomy for a healthy patient who had a lesion >/= 10 mm. This approach minimizes the chance of not treating a premalignant lesion. Most cholesterol and inflammatory polyps are <>/= 12 mm over time, the gallbladder should be removed if possible.