Thyroid cancer occurs when you develop an overgrowth of abnormal cells in the thyroid gland—a butterfly-shaped organ in the front of your neck. The thyroid gland produces hormones that control several major bodily functions, including breathing, heart rate, and digestion. Thyroid cancer— especially in its earlier stages—often causes no symptoms. As it progresses, the condition may cause symptoms such as a lump or swelling in the neck, a hoarse voice, and a cough.1

There are four types of thyroid cancer. Each type is based on the type of cell the cancer develops from and how the cancer grows. About 80% of all cases are papillary thyroid cancer (PTC). Fortunately, this type is highly treatable and very rarely fatal (deadly).2 

Thyroid cancer may develop from an epithelial cell and can range from benign (harmless) to extremely aggressive. For example:3

• Well-differentiated thyroid cancer (WDTC) is relatively benign.
• Anaplastic thyroid cancer (ATC) is rare and extremely aggressive.
• Poorly differentiated thyroid cancer (PDTC) is somewhere in the middle.

Medullary thyroid carcinoma (MTC) is a thyroid cancer that develops from a thyroid C cell.3

People assigned female at birth experience thyroid cancer three times as often as those assigned male at birth. However, the death rate of thyroid cancer is similar regardless of sex.4 The average age of diagnosis for someone with thyroid cancer is 51—which is younger than most other cancers that affect adults.5 Cases of thyroid cancer have been on the rise for the past two decades. That's why knowing what signs to look for and when to reach out for care are so important.6

Lump in the Neck

The first noticeable sign of thyroid cancer is a lump in the front of the neck. This lump is called a nodule. Most nodules are benign, or not cancerous. However, in about 5% to 10% of cases, a thyroid nodule does become cancerous.7 It's worth noting that nodules in the thyroid gland are extremely common. Research shows that many people have one or more of these nodules without ever realizing it.8

While most nodules do not lead to other symptoms, in some cases, you might experience the following symptoms after developing a lump:98

• Pressure, pain, or swelling in the neck
• Trouble breathing or swallowing
• Hoarse voice
• Cough
• Hyperthyroidism (an overactive thyroid)

Pain and Swelling

Thyroid nodules can put pressure on certain areas of your throat. If you develop a thyroid nodule, you might feel pain from your neck and sometimes all the way up to your ears.10

Another possible symptom of thyroid cancer is swelling in the neck. However, swelling is not usually the result of a thyroid nodule. Instead, enlarged lymph nodes, or small glands consisting of immune cells, can make your neck look and feel swollen.11 Lymph nodes contain white blood cells to fight off infections. When your body is trying to fight off thyroid cancer, the lymph nodes in your neck often swell up.12

Trouble Breathing or Swallowing

Pressure from a thyroid nodule may increase your risk of having trouble breathing or swallowing food. A large thyroid nodule can often put pressure on your trachea (windpipe), which may lead to trouble breathing. You might experience increased difficulty with breathing when you're lying down. On the other hand, pressure on your gullet (esophagus) may make it difficult for you to properly eat and swallow food. It's common to also experience some pain when trying to swallow.8

Hoarseness and Cough

It's normal to have a hoarse voice from time to time or if you're recovering from an illness. But, persistent hoarseness can be a sign of thyroid cancer. You might develop a hoarse voice if one or more of your thyroid nodules start putting pressure on your larynx (voice box).4 Nodules on the thyroid gland may irritate your throat and cause coughing. A cough caused by thyroid cancer is typically constant and does not go away over time.10

Hyperthyroidism

Some thyroid nodules produce thyroid hormones. As the nodules grow larger, they may produce too much thyroid hormone. This overproduction of hormones may lead to symptoms of hyperthyroidism. Symptoms may include increased sweating, heart palpitations, blurry vision, and unintentional weight loss.8

Symptoms in Children

Thyroid cancer is rare in children. It's important to note, however, that thyroid nodules in children are oftentimes more cancerous. While the rate of cancerous nodules in adults is between 5% and 10%, this rate is between 19% and 34% in children.7 Children under age 10, especially, often have larger tumors and are at an increased risk of metastasis (or, cancer spreading to other parts of the body).13

When To See a Healthcare Provider

Fortunately, most cases of thyroid cancer are curable with proper treatment. However, as with all cancers, the outlook for people with thyroid cancer is better when they catch the condition early.6 

If you have a lump or swelling in your neck, it's good practice to visit your healthcare provider for an evaluation. Additionally, if you have certain risk factors for thyroid cancer, such as a family history of thyroid cancer or previous radiation exposure, make an appointment as soon as you notice symptoms. Your healthcare provider can perform a physical exam and order a blood test, ultrasound, or biopsy to detect the presence of cancer cells.8