What Is It? Parathyroid cancer is a very rare cancer that
develops in the parathyroid glands. A pair of these pea-sized
glands sits next to the thyroid on either side of the front of
the neck. The four parathyroid glands produce parathyroid
hormone (PTH). This chemical: - Raises calcium levels in the
blood by forcing the bones to release calcium - Stimulates the
intestines to absorb more calcium from food - Signals the
kidneys to withhold calcium from the urine Healthy parathyroid
glands adjust their production of PTH to keep blood calcium
levels within a normal range. When parathyroid cells become
cancerous, they multiply out of control. They usually form a
firm, grayish-white tumor. The tumor can invade the thyroid
gland and neck muscles. As the cancerous cells grow, they
usually produce too much PTH. This causes abnormally high levels
of calcium in the blood (hypercalcemia). PTH can get so high
that the bones pour out too much calcium. This can cause bone
pain and lead to osteoporosis (thin, brittle bones)