Masses originating from any tissues are called tumor. There are two types of tumors: benign and malignant. Tumors may be a few milimeters or tens of centimeters.

Parathyroid tumors usually do not exceed a few centimeters and are often undetectable with physical examination because they are trapped between the muscles of the neck

Benign Parathyroid Tumors

The other name of benign parathyroid tumors are adenoma. Fortunately, 95% of parathyroid tumors are benign, not cancer. Benign tumors never spread to the surrounding tissues via direct invasion or blood and lymphatic vessels.

Malignant Parathyroid Tumors

Other name for malignant parathyroid tumors are parathyroid cancer. They're very rare. When a mass is diagnosed in parathyroid tissue, the probability of being malignant does not exceed 5%. Malignant parathyroid tumors are generally not locally aggressive and metastatic so life threatened effects are related to very high blood calcium levels. This is the major difference of malign parathyroid tumors and the other organ malign tumors. Long term high blood calcium levels may cause contractile disorders in the heart muscle and sudden cardiac arrest.