Several years ago I had a benign cystadenoma on my pancreas removed, along with a part of my pancreas and also my spleen. I began to have symptoms of diabetes last fall and am controlling it with diet. Now, I am having trouble digesting my food and have lost more weight. My doctor has put me on Viokase. I am wondering how common this type of situation is and whether it is likely to get worse.

J.S.

A cystadenoma of the pancreas is a tumor composed of fluid-filled cysts along with glandular tissue. These tumors are most often benign, but they occasionally develop into cancer. Generally, they are discovered by accident when a CT scan of the abdomen is done for other reasons. Since cystadenomas generally do not cause symptoms, they can become quite large before they cause abdominal pain.

When a cystadenoma is discovered, it must be removed to ensure that no cancerous cells are present. Sometimes a large portion of the normal pancreas may need to be removed, in addition to other nearby structures such as the spleen and portions of the stomach or small intestine. In a healthy person, the pancreas helps to regulate blood sugar by producing insulin. It also contributes to digestion by producing digestive enzymes. Usually, a large portion of the pancreas, about 90 percent, must be removed before the function of the pancreas is affected. However, in some patients, scarring may affect the organ's function even if a smaller portion of the pancreas is removed.

Pancreatic deficiency shows up as a rise in blood sugar, which may progress to full-blown diabetes. Therapy includes dietary changes and administration of insulin. A deficiency of digestive enzymes can lead to diarrhea and weight loss. The therapy for this dysfunction is enzyme replacement tablets (Viokase), which patients take before eating.

However, it is puzzling that your condition continues to worsen several years after surgery. Your pancreatic function should have stabilized soon after your original operation. It is possible that your tumor may have recurred, or that a different medical problem is affecting your pancreatic function. You should see your doctor to discuss whether further tests may be appropriate in your case.