Parathyroid adenoma vs. Parathyroid hyperplasia

Hyperparathyroidism can be caused by abnormalities of one of the parathyroid glands or two, three, or all four of the parathyroid glands. Parathyroid disease diagnosis is made by evaluating intact parathyroid hormone levels and calcium levels.

The most common type of hyperparathyroidism is primary hyperparathyroidism. Primary hyperparathyroidism implies that the problem originated in the parathyroid glands. The parathyroid glands are self-regulating in that normally they will produce parathyroid hormone, which will help absorb calcium and help depositing the calcium into the bones. If the parathyroid glands lose their ability to self-control the amount of secretion, levels of parathyroid hormone go up and excess calcium is circulating in the blood and removed from the bones. The most common type of primary hyperparathyroidism is single-gland disease. Typically, this is caused by what is known as a parathyroid adenoma. The parathyroid adenoma is a small benign tumor in one of the four parathyroid glands that over-secretes parathyroid hormone and is not responsive to the self-control mechanism. Parathyroid adenomas are the most common finding in parathyroid surgery. Parathyroid adenomas can be removed simply with minimally invasive parathyroid surgery without disrupting the normal function of the other three glands. Approximately 90% of patients who have primary hyperparathyroidism have single-gland primary parathyroid adenoma. This allows for a simple solution to a serious medical problem by removing the abnormal gland.

Primary hyperparathyroidism can also involve all four glands. In this situation, the glands become hyperplastic but do not form a tumor. The glands may be all hyperactive or several of the four glands may be hyperactive. The possibility of multi-gland adenomas is also a consideration. However, in most cases when more than one gland is involved, consideration must be given to the fact that it may be a diffuse problem of all the parathyroid glands. Therefore, in situations where more than one gland is involved, all four glands should be examined and assessed.

The symptoms of multi-gland disease and hyperplasia are identical to the symptoms associated with a parathyroid adenoma. Both conditions also result in elevated parathyroid hormone and a high blood calcium level. The difference however is in the treatment. Treatment of hyperplasia is much more complicated and should be performed by surgeons who are experienced in treating hyperplastic glands. The treatment involves removal of portions of all the glands and in many cases complete removal of at least two of the glands. Preservation of a portion of these glands however is essential. The preservation has to be done on a small vascular pedicle in order to allow the remaining parathyroid tissue to function. In some situations, parathyroid hyperplastic tissue is removed and then re-implanted into the muscle. The results of multi-gland surgery are excellent when done by experienced parathyroid surgeons. Often the preoperative nuclear scan of patients with hyperplasia will be different than the scan of those patients with a solitary adenoma. Patients that have hyperplasia will often have what is known as a 'negative scan' where there is no significant uptake in any of the glands. They also might have multiple areas of uptake. Both negative gland and a multi-gland uptake on a nuclear medicine scan indicate a possibility of multi-gland hyperplasia.