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Approved by the Cancer.Net Editorial Board, 09/2022

About gallbladder cancer

Gallbladder cancer occurs when healthy cells in the gallbladder change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.

This section is about primary gallbladder cancer. Primary gallbladder cancer is cancer that starts in the gallbladder. This is different than when cancer begins somewhere else in the body and spreads to the gallbladder.

About the gallbladder

The gallbladder is a pear-shaped organ located just under the liver. It is part of the body’s biliary tract, along with the liver and bile ducts. The gallbladder stores bile, a fluid made by the liver that helps to digest fats. Bile travels through the liver to the gallbladder through the intrahepatic bile ducts for storage. It is released from the gallbladder through a tube called the common bile duct as food is broken down in the stomach and small intestine.

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

  • Mucosa: 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.