... cells." Your thyroid is a small, butterfly-shaped gland in your neck. Normally, you have a small amount of calcitonin in your blood. But if you have too much, it may be a sign of: Medullary thyroid cancer (MTC) , a rare cancer that happens when C cells in your thyroid grow out of control. C cells grow in the inside part of your thyroid, which is called the medulla. C-cell hyperplasia , a rare condition that causes abnormal growth of C cells in your thyroid. C-cell hyperplasia can turn into medullary thyroid carcinoma. Your health care provider may order a calcitonin ...

... makes. Your thyroid is a small, butterfly-shaped gland in your neck. It makes hormones that control many activities in your body, including your heart rate and how fast you burn calories from food. A thyroglobulin test is a type of tumor marker test . Tumor markers are substances made by cancer cells and/or by normal cells in response to cancer in your body. Normally, your thyroid releases small amounts of thyroglobulin into your bloodstream. Cells from common types of thyroid cancer (papillary carcinoma and follicular thyroid cancer) also release thyroglobulin. Thyroglobulin ...