Parathyroid cancer is extremely rare. It does exist, but it is so uncommon that most doctors will never see it. Nearly all parathyroid tumors are benign, even if cancer runs in your family or if you have had cancer in the past. 

The treatment for both benign parathyroid tumors and cancerous parathyroid tumors is parathyroidectomy, removal of the diseased parathyroid. Although parathyroid tumors are benign, they can still cause significant damage to your health, which is why we recommend surgery.

More about parathyroid cancer: it would generally present with very high calcium and PTH numbers - but benign parathyroid tumors can present with these numbers also, so this is not definitive. Parathyroid cancer cannot be diagnosed with a needle biopsy - in general, parathyroid tumors should not be needle biopsied. Most of the time, parathyroid cancer would only be diagnosed after surgery if the parathyroid tumor was found to be invading surrounding structures. Note, though, that even this is not always clear - a parathyroid biopsy (sticking a needle into the parathyroid tumor) can produce a dramatic inflammatory reaction around the parathyroid that can make it appear that the parathyroid is invading surrounding structures, even when it is not. Also, very old parathyroid tumors tend to get “sticky” - they stick more to surrounding structures, but they are not invading them. 

If you have been diagnosed with primary hyperparathyroidism, the odds are overwhelmingly in favor of you having a benign tumor. Parathyroid cancer is so rare that it is usually not even a consideration.