Adapted for the Canadian edition by Donald A. J. Sutherland, MD, PhD
The parathyroid glands are usually located in the neck, two on each side of the thyroid gland
( see "Thyroid" ).
Parathyroid cancer is a rare and sometimes curable endocrine gland cancer. Though not all these tumors are functioning, those that are produce increased amounts of parathyroid hormone (parathormone), which leads to a marked elevation in blood calcium level (hypercalcemia). It is usually the signs and symptoms of elevated calcium that lead to the diagnosis.
Benign tumors of the parathyroid (adenomas) and an overgrowth of parathyroid tissue (hyperplasia) are much more common (99 percent) than malignant tumors (1 percent). These also produce parathyroid hormone and elevated blood calcium levels, so it is sometimes difficult to know at surgery if the tumor is benign or malignant. This distinction is extremely important because the treatment of a malignant parathyroid tumor requires not only removal of the tumor but removal of the thyroid gland on that side. Adjacent muscles and tissues are also removed if they are affected by cancer.
