What are the characteristics of thyroid cancer: Thyroid cancer is a malignant tumor originating from the thyroid tissue, which usually grows slowly and the clinical symptoms are not obvious. If you find any of the following symptoms, you should seek medical attention immediately: 1. lump or nodule in the neck (front or side) 2. hoarseness or change of voice 3. difficulty in swallowing or breathing 4. enlarged lymph nodes in the neck What are the types of thyroid cancer: Thyroid cancer is mainly divided into three types 1. differentiated thyroid cancer (mainly papillary and follicular carcinoma) 2. medullary carcinoma 3. undifferentiated thyroid cancer 90% or more Thyroid cancer is differentiated thyroid cancer. Most differentiated thyroid cancers progress slowly. Active treatment is usually very effective.