Thanks for writing. Your scenario is fairly common. Your labs are classic for primary hyperparathyroidism (high calcium and high PTH), but your parathyroid scans are negative (no parathyroid tumors seen).

So what should you do to lower the calcium and PTH?

Short answer: A parathyroid operation.

Long answer: Parathyroid surgery is the only way to cure primary hyperparathyroidism. There are medications that can temporarily drop the calcium or PTH level, but they are not cures, and they do not cure the symptoms or prevent complications of parathyroid disease.

You do not need a positive scan in order to have parathyroid surgery. This is a very common misconception. Parathyroid tumors are often small and may never show up on a scan. This goes against how we normally think about tumors. We usually evaluate tumors with imaging. Most tumors in the body are diagnosed by either seeing or feeling a lump, or viewing a growth on a scan. This is not true for parathyroid tumors. Parathyroid tumors are endocrine tumors, which are diagnosed by the activity of hormone levels rather than the presence of a mass on scan. Endocrine tumors can cause major health issues even when they are tiny.

Parathyroid glands are generally about the size of a grain of rice. The tumor grows within this gland and enlarges the entire gland, but may still only be about the size of a small raisin. None of our scans are great at seeing these small tumors. This is especially true because parathyroid glands are usually right next to the thyroid, and can “blend in” with the thyroid.

Many of my patients have completely negative scans. They have classic primary hyperparathyroidism, but no parathyroid tumors shown on any scans. When I operate, I evaluate all four parathyroid glands and will quickly figure out which parathyroid glands are abnormal.

Also note that even when scans show a diseased parathyroid, they are not always accurate! About 25% of patients will have more than one diseased parathyroid gland, and it is very rare for that to show on a scan. Meaning, only one parathyroid tumor shows up, but there is another parathyroid tumor that will only be found if the surgeon looks at all of the glands during the operation. If the surgeon only removes the one seen on scan, but doesn’t look at the others, the patient is not going to be cured, and will need another operation in the future.

For people with primary hyperparathyroidism, I recommend finding an experienced surgeon who is comfortable with finding and evaluating all four parathyroid glands during surgery. An experienced surgeon will not rely on imaging studies to determine which parathyroid gland is bad.