The most common cause of excess hormone production (hyperparathyroidism) is the development of a benign tumor in one of the parathyroid glands. This enlargement of one parathyroid gland is called a parathyroid adenoma which accounts for about 70 percent of all patients with primary hyperparathyroidism (the other 30% will have more than one bad gland, see chart below). This out of control parathyroid gland is essentially never cancerous (virtually 100% of them are benign tumors), however, it slowly causes damage to the body because it induces an abnormally high level of calcium in the blood which can slowly destroy a number of tissues. Parathyroid adenomas typically are much bigger than the normal "grain-of-rice" parathyroid and will frequently be about the size of an olive or grape. Thus, the typical patient with hyperparathyroidism will be cured of the disease when this "olive" size tumor is removed. Up to 30% will have more than one tumor, so your surgeon should test to make sure the others are all good. People live Hyperparathyroidism: Typical Parathyroid Adenoma
Typical Parathyroid Adenoma Causing Hyperparathyroidism
just fine with less than four normal parathyroid glands that will be about the size of a grain of rice. The picture to the left is a picture of a typical parathyroid adenoma (parathyroid tumor) that causes hyperparathyroidism. This is a very average tumor size, shape, and color. Most people with hyperparathyroidism will have a tumor in their neck about this size, some will have two. Remember, the normal parathyroid gland is about the size of a grain of rice... but one cell inside this normal parathyroid gland went out of control and started reproducing itself until a large tumor developed. This tumor will almost always continue to grow until it is removed. As it grows, it makes more hormone and will make you feel worse. This tumor is constantly making parathyroid hormone which is what takes the calcium out of your bones and makes the calcium in your blood too high. (We have an entire page of photographs of parathyroid tumors so you can see what these little boogers look like!).
Where did this parathyroid tumor come from? This is a great question, and the answer is quite simple... In most cases we don't know WHY parathyroid tumors form. But this is HOW a parathyroid tumor forms: The normal parathyroid gland is made up of about 80,000 very small parathyroid cells. Each one is exposed to lots of blood flow and they all measure the calcium in the blood. When the calcium is low, they make parathyroid hormone (abbreviated PTH). When the calcium is high, they stop making hormone. They normally turn on and off hundreds of times per day. All of these cells act independent of the other. Occasionally, one of these cells will go nuts and start reproducing itself... a million or more times. The crazy "mother" cell divides into two, then does it again, and again, and again; many times a day. Over a period of several years a tumor develops. This tumor mass (seen in the photos on this site) is made up of millions of cells all of which are sisters from one crazy "mother" cell. Each of these "daughter" cells inherited the craziness of the mom, and they don't pay attention to the calcium level in the blood. They are out of control, making PTH whenever they want, in as much concentration as they want. When you look at all the pictures of the parathyroid tumors on this web site, you will see a small (rice-size) yellow NORMAL gland with a dark-red tumor growing out of it. The tumor mass is composed of millions of crazy daughter cells from one mother cell that went nuts. If you have surgery at the Norman Parathyroid Center, you will get a photo of your tumor, and you can almost always see the normal gland from which the tumor arose.
This graph shows the blood parathyroid hormone levels in 18,000 patients operated on at the Norman Parathyroid Center for primary hyperparathyroidism. Normal blood levels of parathyroid hormone vary according to the lab that measures the hormone, but most labs have a normal level between 15 and 65 pg/ml. Each of the patients represented here had a parathyroid tumor removed from their neck. As you can see, most (but not all!) of them have parathyroid hormone levels that are above normal (above 65).