excerpts from VHL Handbook
Pancreatic lesions are generally considered to be the least symptomatic among the lesions of von Hippel-Lindau disease. However, patients report a number of subtle symptoms which may be caused by pancreatic cysts.
Three types of lesions may be found commonly in the pancreas:
(2) Serous microcystic adenomas, or “cystadenomas”
(3) Islet cell tumors, or pancreatic neuroendocrine tumors (NET)
Pancreatic cysts may be found in a large number of people with VHL, with wide variation among families. About 75% of people with VHL develop pancreatic cysts. Many cysts, even very large ones, may be present without causing symptoms, in which case no treatment is required. In some cases, enlarged cysts may press against the stomach and cause discomfort. Surgical drainage of a large cyst may provide relief.
Pancreatic tumors are found in about 12% of people with VHL. Serous microcystic adenomas (benign tumors) are the most common. These generally do not need to be removed unless they are causing obstructions to the normal flow of fluids and enzymes that cannot be managed otherwise.
Depending on their size, type, and location, VHL cysts and tumors of the pancreas can cause functional problems as well as structural problems. The medical team may request additional tests to detect abnormal hormonal function. The job of the pancreas is to create hormones and enzymes that are important to the digestion of the food, making the nutrients in the food available to the body’s cells. Cysts and tumors may block one or more of the ducts that carry essential fluids from the pancreas to the digestive tract, causing diarrhea, constipation, fatty stools, other digestive complaints, and weight loss. Blockage of the delivery of insulin may cause digestive problems or diabetes. Fortunately, there are replacements that can be taken by pill or injection. Insulin or digestive enzymes may need to be prescribed to maintain health. Figuring how much of which enzyme is needed at what times is not an easy thing to calculate. A gastroenterologist or naturopath familiar with pancreatic insufficiency and digestive imbalance can assist in achieving the right balance to improve quality of life.
If lesions obstruct the bile ducts, there may be jaundice, pain, inflammation or infection. Jaundice is when the skin and urine become yellow, and the stools become quite pale. Pain is the body’s signal that there is something wrong and requires attention. Seek medical help immediately, as pancreatitis is a serious condition requiring medical attention.
The most worrisome pancreatic issue is solid tumors, not cysts, arising within the islet cells of the pancreas. These may be pancreatic neuroendocrine tumors (Pancreatic NET or pNETs), which can cause bile duct obstructions and can even metastasize or spread to the liver, bone, or other organs.
Some of the “hard tumors” turn out to be microcystic adenomas, honeycombed clusters of small cysts that look solid on the scans but, in fact, are not a problem.
Careful evaluation of pNETs is critical because it would be best not to operate on the pancreas unless it is important to do so. PNETs are not “functional” in VHL, meaning they do not emit hormones, so chemical tests will not help to determine their nature.
Although MRI is the preferred screening method for the abdomen, a CT may be needed to answer a specific diagnostic question, especially if there are symptoms. There are several advantages when evaluating pNETs. CT provides a superior anatomic study to MRI and helps to plan an operation as relationships of the tumor to other structures are more easily discerned. The most sensitive and specific study for diagnosing pNETs is an early arterial phase CT scan. CTs are also less subject to motion artifact variability between different machines, allowing more accurate monitoring of changes in the size of the lesion. The recommended CT is a three phase contrast (early arterial, portal, delayed) scan. A 12-year study at the US National Institutes of Health identified three variables that are important in deciding whether intervention is required—size, behavior, and the nature of the DNA alteration.
DNA: Research has shown a higher correlation of dangerous pNETs among people who have an alteration in exon 3 of the VHL gene. The VHL gene has three distinct parts, called exons. Each family has a particular mutation, like a misspelling of one word in the book of instructions that make up the VHL protein. That family mutation is passed intact from parent to child, so each family member has the same alteration in their VHL gene. People with a mutation in exon 3 seem to have a more aggressive type of pancreatic tumor.
Behavior: Researchers also looked for signs of aggressive behavior. To measure aggressiveness, they took a series of images and compared the size of the largest tumor in each of these scans, then calculated its rate of growth, or “doubling rate.” If the tumor doubled in size in less than 500 days, it was deemed to be high risk. If it took longer than 500 days for the tumor to double, it was at a more moderate risk level.
Size: In the past, recommendations for when to operate have been based entirely on size. But now, with the addition of these new measures, Dr. Steven Libutti at Rutgers Cancer Institute of NJ, has divided tumors into three categories—low risk tumors can be watched every 2–3 years; medium risk tumors should be followed more closely, and high-risk tumors should be evaluated for surgery.
Possible effects on pancreatic function
While cysts are benign (they do not become cancerous), they may block one or more of the tiny tubules in the pancreas that deliver insulin, glucagon, or pancreatic enzymes to the gut. It is somewhat like stepping on the garden hose. Even though the pancreas is still making these hormones and enzymes, they are unable to get to where they need to go to aid digestion.
Diabetes is the condition that occurs when the pancreas does not make enough insulin to keep blood sugar within the normal range. This can be treated with pills that can help the pancreas make more insulin, or pills that tell the liver to make less sugar, or injections of insulin to replace what is not getting produced or delivered. An endocrinologist and a certified diabetes educator (dietitian or nurse) can help with the management of diabetes and help develop a personalized plan for meals and exercise.
Tumors near the common bile duct can also block the gallbladder from delivering bile. Blockages near the liver can affect liver function. Be sure to discuss any pain or yellowing of skin or eyes with a doctor. These symptoms of jaundice may indicate a problem with liver function.
Pancreatic insufficiency is when the pancreas is not making the digestive enzymes, or when their delivery to the gut is blocked. Removal of all or part of the pancreas clearly reduces the ability of the pancreas to make and deliver these enzymes. When the food is not broken down, the nutrients cannot be delivered to the cells. The food simply goes right on through and out the other end without being digested and absorbed. In other words, the cells are still starving. This condition is called “malabsorption.” One major sign of malabsorption is loss of weight. It is critically important to your health to get your digestion back in balance. This is more than an annoyance; it is one of the keys to your health and the strength of your immune system.
Symptoms of malabsorption include diarrhea, bloating, cramping, abdominal pain, fatty stools (appear frothy and oily on the top of the toilet bowl water, with a strong odor), and possible deficiencies of fat-soluble vitamins (A, D, K, and E). A registered dietitian who works with clients with cystic fibrosis, pancreatic cancer, or pancreatic insufficiency should be able to help with this problem.
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