Pancreatic adenocarcinoma: An adenocarcinoma is a cancer that starts in gland cells.. These cancers usually begin in the ducts of the pancreas. But sometimes they develop from the cells that make the pancreatic enzymes, in which case they are called acinar cell carcinomas.
Less common types of cancers: Other cancers of the exocrine pancreas include adenosquamous carcinomas, squamous cell carcinomas, signet ring cell carcinomas, undifferentiated carcinomas, and undifferentiated carcinomas with giant cells. These types are distinguished from one another based on how they look under the microscope although their treatment is often similar to pancreatic adenocarcinoma.
Solid pseudopapillary neoplasms (SPNs): These are rare, slow-growing tumors that almost always occur in young women. Even though these tumors tend to grow slowly, they can sometimes spread to other parts of the body, so they are best treated with surgery. The outlook for people with these tumors is usually very good.
Ampullary cancer (carcinoma of the ampulla of Vater): This cancer starts in the ampulla of Vater, which is where the bile duct and pancreatic duct come together and empty into the small intestine. Ampullary cancers aren’t technically pancreatic cancers, but they are treated very similar to pancreatic adenocarcinoma.
Based upon the location of the pancreas, tumors are often able to grow in silence without the patient knowing anything is wrong. For slow-growing tumors or cysts, this can result in very large tumors by the time they are found. However, in more aggressive tumors such as pancreatic adenocarcinoma, this can lead to the cancer spreading before being discovered. The type of symptoms often depends on the location of the tumor. When they start in the left side of the pancreas (body or tail), symptoms are often very vague, such as dull abdominal or back pain, a “full” sensation when eating, or unintentional weight loss. However, a tumor starting in the head of the pancreas on the right side can block the bile duct. This results in bile backing up into the liver and causing jaundice where the skin and eyes turn yellow, the urine turns very dark, the stool can turn whitish in color, and itching of the skin can occur. Sometimes patients can develop diabetes unexpectedly up to a year before being diagnosed with pancreatic cancer.
Tumors of the endocrine pancreas are uncommon, making up less than 4% of all pancreatic cancers. As a group, they are sometimes known as pancreatic neuroendocrine tumors (NETs) or islet cell tumors.
Pancreatic NETs can be benign or malignant (cancer). Benign and malignant tumors can look alike under a microscope, so it isn’t always clear whether or not a pancreatic NET is cancer. Sometimes the diagnosis only becomes clear when the tumor spreads outside of the pancreas.
There are many types of pancreatic NETs.
Functioning tumors: About half of pancreatic NETs make hormones that are released into the blood and cause symptoms. These are called functioning tumors. Each one is named for the type of hormone being made that leads to symptoms:
The most common types of functioning NETs are gastrinomas and insulinomas. The other types occur very rarely.
Non-functioning tumors: These tumors often make hormones but not in amounts that cause symptoms. Because they don’t make excess hormones that cause symptoms, they can often grow quite large or spread to other organs before they are found.
Carcinoid tumors: These are another type of NET that can start anywhere in the digestive system including the pancreas but most commonly start in the intestines. These tumors often make serotonin (also called 5-HT) or its precursor, 5-HTP which can lead to carcinoid syndrome where people have flushing in the skin of the face or chest and profuse diarrhea.
The treatment and outlook for pancreatic NETs depend on the specific tumor type and the stage (extent) of the tumor, but the outlook is generally better than that of pancreatic exocrine cancers.