Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Parathyroid Cancer ?
    ### Response:
    Key Points
                    - Parathyroid cancer is a rare disease in which malignant (cancer) cells form in the tissues of a parathyroid gland.    - Having certain inherited disorders can increase the risk of developing parathyroid cancer.     - Signs and symptoms of parathyroid cancer include weakness, feeling tired, and a lump in the neck.
    