Symptoms and diagnosis of thyroid cancer

Thyroid cancer is diagnosed at an average age of 58. It usually presents as a nodule found incidentally during palpation of the neck or an imaging test (CT, PET scan, or carotid Doppler) performed for some other reason. In a few cases, patients notice neck discomfort or voice changes. 
Some medullary thyroid cancers can cause symptoms related to excess calcitonin production, such as flushing (hot flashes, redness) or diarrhea, that also aid in diagnosis. Doctors can determine whether the cancer is medullary by measuring calcitonin levels. They can also question patients about their personal and family medical history.
Thyroid nodules are fairly common and increase with age (20% at age 20, 30% at 30, 50% at 50, etc.); however, only about 5% to 10% of those nodules are malignant².

Institut Curie offers a specialized program for examining thyroid nodules and determining whether they are cancerous or benign. The Thyroid Nodule Pathway is staffed by endocrinologists, radiologists and other medical experts. They can diagnose potentially malignant nodules by conducting a series of additional tests (blood tests, neck imaging, cytopuncture) based on the nodule’s appearance (such as an irregular margin or microcalcifications) or size. By analyzing the cells after cytopuncture, they can assign the nodule to a malignancy risk category using the international Bethesda system, which includes standardized diagnostic criteria and treatment practices for thyroid nodules. The Bethesda classification includes six cytological categories and offers recommendations for each one. It also lays out treatment options that are discussed at a multidisciplinary consultation meeting (MCM). 
 

[2] Source : InfoCancer