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I had parathyroid surgery last week - two glands were removed. The biopsy came back as hyperplasia instead of adenoma. My understanding is that if it is hyperplasia, all FOUR glands are affected. My surgeon did find a 3rd gland "lumped in" next to one of the enlarged glands and he originally took it as well, upon further inspection, realized it was not part of the bad gland and appeared normal, so he re-implanted it. He did NOT look at the 4th gland at all. My question is, since the pathology came back as hyperplasia instead of adenoma, will I need another surgery at some point to remove the other gland?

Deva Boone
Answer authored by Deva Boone
Deva Boone, MD is the founder of the Southwest Parathyroid Center. As one of the most experienced parathyroid surgeons in the U.S., she has treated thousands of patients with parathyroid conditions.

Thank you for bringing up this really important topic!

The full answer to your question is complicated, so here is the brief summary: Pathology is not used to determine whether you had adenomas or hyperplasia. In most cases, we can’t determine hyperplasia vs. adenoma on pathology slides. The report is really just confirming that your surgeon removed parathyroids. An adenoma may be called “hypercellular parathyroid,” “parathryoid adenoma,” or “parathyroid hyperplasia” on the pathology report. Basically, you can ignore the results.

Here is the longer answer: There is a very good chance that you simply had two adenomas. The way to figure out what is going on is to look at your lab values. If your calcium was high before the operation and is no longer high, and your PTH is normal, then you are cured, whether you had adenomas or hyperplasia. If your calcium level is still high, then there is a chance that you are not cured, and may need another parathyroid operation. Not that it doesn’t matter too much whether you have another adenoma or hyperplasia, because either way, you have another abnormal parathyroid gland.

About pathology reports: It helps to understand what the pathologist is actually looking at and commenting on. They are slicing up the parathyroids that were removed and looking at them under the microscope. Parathyroid glands look a certain way. When you look at them under the microscope, you will see parathyroid cells interspersed within fat. If you have about a normal ratio of fat to parathyroid cells, then you have normal cellularity, or “normocellularity”. If there is very little fat compared to the number of parathyroid cells, then you have a high cellularity, or “hypercellularity”. The pathologist doesn’t have a lot more to say about those glands. Both hyperplasia and adenomas will tend to show hypercellular glands. In many cases, adenomas and hyperplastic glands look the same under the microscope.

Note: There is one way in which adenomas MIGHT be described differently from hyperplasia. If the pathologist comments on seeing a discrete “hypercellular area surrounded by normocellular rim of parathyroid” then that indicates an adenoma. The adenoma is the growth of hypercellular parathyroid cells within the normal parathyroid. But note that in most cases of adenomas, the pathologist does NOT see that rim, and will not comment on it. It is still an adenoma!

Another caveat on pathology: We like to think of “normocellular” glands as being normal parathyroid, and “hypercellular” glands as being abnormal (either hyperplasia or adenomas), but even this is not always the case. Normal parathyroid glands have a wide range of what is normal cellularity - and it will vary even throughout the individual gland! If you are looking at just a small piece of a gland (like a tiny biopsy) then you may happen to see an area that is hypercellular, even though the gland is normal. In about half of my biopsies of what are clearly normal glands (tiny, soft, yellow-orange color) the pathology report calls the piece “hypercellular”. This does not mean that the patient has hyperplasia, but simply that the gland had a higher cellularity in that tiny piece of the biopsy, which is normal.

Operation Pathology