What Is Gallbladder Cancer?

About the gallbladder

The gallbladder is a small, pear-shaped organ under the liver. Both the liver and the gallbladder are behind the right lower ribs. In adults, the gallbladder is usually about 3 to 4 inches long and normally no wider than an inch.  The liver makes bile and it is either sent into ducts that carry it to the small intestine or stored in the gallbladder and concentrated and released later. Bile helps digest the fats in foods as they pass through the small intestine.

The gallbladder’s wall is made up of 3 main layers of tissue:

• Mucosa (the epithelium and the lamina propria): The innermost layer of tissue that covers the wall of the gallbladder.
• Muscularis: The middle layer of smooth muscle.
• Serosa: The outer layer of tissue.

Primary gallbladder cancer begins in the inner layer and spreads into the outer layers as it grows.

The gallbladder helps digest food, but you don't need it to live. Many people have their gallbladders removed and go on with their everyday lives.

Types of gallbladder cancer

Gallbladder cancers are rare, and nearly all of them are adenocarcinomas. An adenocarcinoma is a cancer that starts in gland-like cells that line many surfaces of the body, including the inside of the gallbladder.

Papillary adenocarcinoma of the gallbladder is a rare type of gallbladder cancer that deserves special mention. The cells in this gallbladder cancer are arranged in finger-like projections. Papillary adenocarcinomas are less likely to spread into the liver or nearby lymph nodes. They tend to have a better prognosis (outlook) than most other kinds of gallbladder cancers.

Other types of cancer that can start in the gallbladder include: 

• Adenosquamous carcinomas
• Squamous cell carcinomas
• Small cell neuroendocrine tumors
• Sarcoma
• Lymphoma (these are very rare)