There are lots of different types of cells in the gallbladder. Any of these cell types could, in theory, develop into cancer that’s why there is more than one type of gallbladder.
More than 85 out of every 100 gallbladder cancers (85%) are adenocarcinomas. This means that the cancer started in gland cells in the gallbladder lining. The gland cells normally produce mucus (thick fluid). There are three types of adenocarcinomas of the gallbladder.
More than 75 out of every 100 gallbladder cancers (75%) are non-papillary adenocarcinomas. Only about 6 out of every 100 diagnosed gallbladder cancers (6%) are papillary adenocarcinomas. These develop in the tissues that hold the gallbladder in place (connective tissues). This type of gallbladder cancer is less likely to spread to the liver and nearby lymph nodes. It tends to have a better outlook than most other types of gallbladder cancer. With mucinous adenocarcinomas, the cancer cells are often in pools of mucus, which is how the cancer gets its name. Only about 1 or 2 out of every 100 gallbladder cancers (1 or 2%) are mucinous adenocarcinomas.
Squamous cell cancers develop from the skin like cells that form the lining of the gallbladder, along with the gland cells. Doctors treat these cancers in the same way as adenocarcinomas.
Adenosquamous carcinomas are cancers that have both squamous cancer cells and glandular cancer cells. Your doctor may call this a mixed histology. Doctors treat these cancers in the same way as adenocarcinomas.
Small cell carcinomas are also called oat cell carcinomas. They are called this because the cancer cells are a distinctive oat shape.
Sarcoma is the name for a cancer that affects the supportive or protecting tissues of the body - also called the connective tissues. Muscles, blood vessels and nerves are all connective tissues. A cancer that begins in the muscle layer of the gallbladder is a sarcoma.
Neuroendocrine tumours are rare cancers that grow from hormone producing tissues, usually in the digestive system. The most common type of neuroendocrine tumour is called carcinoid.