Thyroid cancer symptoms are not always easy to detect, which occasionally makes it hard to diagnose as well. However, all symptoms are not necessarily caused by thyroid cancer at all, but rather by a thyroid nodule. And thyroid nodules are not always cancerous--as a matter of fact, nearly all of them are benign and develop later in life. The following are some symptoms of thyroid cancer that can start as nodules and develop into something more serious.