Types of thyroid cancer
There are different types of thyroid cancer. The type you have depends on the type of cell the cancer started in. The most common type is called differentiated thyroid cancer.
Diagnosing your type of thyroid cancer
Your doctor finds out your type of cancer by taking a small sample of cells (a biopsy) from your thyroid. A 
then examines the cells under a microscope. The cells look different, depending on the type of thyroid cancer.
Differentiated thyroid cancer
The cells in differentiated thyroid cancers (DTC) have some features of normal thyroid gland cells. DTC usually grows slowly. They are divided into 3 groups – papillary, follicular and Hürthle cell thyroid cancer.
Papillary thyroid cancer
This is the most common type of thyroid cancer. About 90 out of every 100 thyroid cancers (about 90%) are papillary.
This type is more common in women and is usually diagnosed in younger people.
It is usually slow growing, but it can sometimes spread to lymph nodes in the neck or close to the thyroid.
Follicular thyroid cancer
Follicular thyroid cancer is most often diagnosed in middle aged people and it is more common in women. Just over 4 out of every 100 thyroid cancers diagnosed (just over 4%) are this type.
Follicular thyroid cancer sometimes spreads to other parts of the body, such as the lungs or bones.
Hürthle cell thyroid cancer
Hürthle cell cancer is a rare type of thyroid cancer. It is usually grouped with follicular thyroid cancers as there are some similarities.
Hürthle cells look different to follicular cells when seen under a microscope. The cells are also called oxyphilic cells, so this cancer is sometimes called oxyphil cell cancer. Hürthle cell tumours can be non cancerous (benign) or cancerous (malignant).
Nearly 2 out of every 100 thyroid cancers (nearly 2%) are this type. It is most often diagnosed in older people and in women.
Medullary thyroid cancer
This is a rare type of thyroid cancer. Nearly 2 out of every 100 thyroid cancers (nearly 2%) are this type.
About a quarter (about 25%) of medullary thyroid cancers are caused by an inherited faulty gene which runs in the family.
Medullary thyroid cancer can spread to other parts of the body, such as the liver or lungs.
Anaplastic thyroid cancer
This is the least common and most serious thyroid cancer. Less than 1 out of every 100 thyroid cancers (less than 1%) are this type.
Anaplastic thyroid cancer is usually diagnosed in older people and is more common in women.
It is called undifferentiated because the cancer cells do not look very like normal thyroid cells. It tends to grow more quickly than other types of thyroid cancer.
Rare types
It is possible for a lymphoma to develop in the thyroid gland. A primary thyroid lymphoma is a type of non-Hodgkin lymphoma and treatment is similar to that of a lymphoma.
Another rare type of thyroid cancer is sarcoma of the thyroid gland. This might be treated with surgery, chemotherapy or radiation.
