What if my scans are normal?

It is quite common for an endocrinologist to confirm a diagnosis of primary hyperparathyroidism with lab work and then order one or more scans to look for an abnormal gland. It is important to understand that it is not necessary to see an abnormal gland on imaging before an operation to know that you have primary hyperparathyroidism. But it seems that endocrinologists tend to want to “hedge their bets” before referring a patient for surgery. In addition, there are many surgeons who don’t feel comfortable considering surgery without having a scan that shows a single abnormal gland.

The most experienced parathyroid surgeons feel quite comfortable proceeding with surgery even if scans are normal. They know that if the lab work confirms the diagnosis, then they will be able to identify the abnormal gland or glands at surgery, regardless of the scan findings. The scans are quite helpful as a roadmap in preparation for surgery. But the imaging should not be the determining factor.

Why do scans sometimes look normal? Parathyroid glands are tiny and sit close to the thyroid. Normal glands are almost never seen, and a small overactive gland may blend in, or it may sit behind the thyroid or lower in the neck where it’s hard to see. Ultrasound is also operator-dependent: subtle findings can be missed by people who do not perform or read these tests often. An expert review can sometimes spot clues that others overlook. Although an abnormal parathyroid gland might not be seen on a sestamibi scan if it sits behind the thyroid (its usual location), it is hard to miss if it sits somewhere else. It is important for the surgeon to know if an abnormal gland is in an ectopic location, because those are the ones that might not be found even by an experienced surgeon. As long as the sestamibi scan doesn’t show an abnormal location for the parathyroid gland, the surgeon can confidently go ahead with surgery, even if the scan is read as normal.

Bottom line: Don’t delay treatment you need while waiting for a scan to “light up.” If your labs confirm primary hyperparathyroidism, talk with a surgeon who treats this every week and can walk you through cure rates, risks, and next steps for you.

This information is educational and not a substitute for medical advice. Talk with your own clinician about your situation.