Stages and types of thyroid cancer
There are different types of thyroid cancer. These include:
papillary thyroid cancer
follicular thyroid cancer
oncocytic cell thyroid cancer – doctors used to call this Hurthle cell thyroid cancer
medullary thyroid cancer
anaplastic thyroid cancer
There are also some rarer types.
Papillary thyroid cancer is the most common type.
Doctors group (classify) thyroid cancers into different types. They use a system which they regularly update. The latest system is the World Health Organisation (WHO) classification of 2022.
Based on the latest WHO classification, we give a simple description of some of the types. You can also speak to your doctor or nurse specialist for more information about your diagnosis.
To diagnose thyroid cancer, a specialist doctor () examines a sample of thyroid under the microscope. They look at several factors to group the different types of thyroid cancers. These factors include:
There are 2 main types of cell in the thyroid gland. These are:
follicular cells
C cells, that make calcitonin
Most thyroid cancers start in follicular cells. This includes:
papillary thyroid cancer
follicular thyroid cancer
oncocytic thyroid cancer
A small number of thyroid cancers start in the C cells. Doctors call these medullary thyroid cancers.
Differentiation means how different the thyroid cancer cells look under a microscope, compared to normal thyroid cells.
Thyroid cancer can be:
differentiated - the cancer cells look a lot like normal thyroid cells
poorly differentiated - the cancer cells look less like normal thyroid cells
undifferentiated - the cancer cells do not look or behave like normal thyroid cells
Most thyroid cancers are differentiated thyroid cancers.
The grade of a cancer tells you how the cancer might behave. The grade depends on what the cells look like, as well as other factors including:
how many cells are dividing (the mitotic count) – this shows how quickly the cancer might grow
how much dying tissue there is (necrosis)
Your doctor looks to see if there are certain changes in the cancer cells. These tests are also called molecular testing or molecular analysis. The results of these tests help the doctors work out your type of thyroid cancer.
Differentiated cancers that start in follicular cells make up about 90 out of 100 thyroid cancers (about 90%). Differentiated thyroid cancers tend to grow slowly. These include papillary, follicular and oncocytic thyroid cancer.
This is the most common type of thyroid cancer. It is more common in women and is most common in people in their 30s and 40s.
It is usually slow growing, but it can sometimes spread to in the neck or close to the thyroid.
Follicular thyroid cancer is most common in people aged between 40 and 60 and it is more common in women.
Follicular thyroid cancer sometimes spreads to other parts of the body. This can include the lungs or bones.
Oncocytic thyroid cancer is a rare type of thyroid cancer. It shares some similarities with follicular thyroid cancers, but they look different. Doctors also call them oxyphilic cells, so this cancer is also known as oxyphil cell cancer.
Oncocytic tumours can be non cancerous (benign) or cancerous. Benign tumours are also known as oncocytic adenomas. Oncocytic thyroid cancer can sometimes spread to other parts of the body.
Oncocytic thyroid cancer is most often diagnosed in people older than 40, and is more common in women.
A pathologist looks at the thyroid cancer under a microscope to find out its type and grade. They look at a number of features. Some follicular, papillary or oncocytic thyroid cancers are high grade. This means they have features such as:
a high number of cells dividing (a high mitotic count)
areas of dying cancer tissue (necrosis)
Doctors call these high grade follicular derived thyroid cancers. Depending on how abnormal the cells look, these include:
differentiated high grade thyroid cancer
poorly differentiated thyroid cancer
These rare cancers tend to grow more quickly than other types of thyroid cancer.
Differentiated high grade thyroid cancer cells still look similar to normal thyroid cells. But they have other high grade features.
Doctors often diagnose these at a later stage compared to other types of thyroid cancer. Some treatments might not work as well and you might need more intense treatment. Your doctor might follow you more closely when you finish treatment. This is in case the cancer comes back.
The cells in poorly differentiated thyroid cancer look less like normal thyroid cells than differentiated thyroid cancer cells. These rare cancers tend to grow more quickly than other types of thyroid cancer.
This is a rare type of thyroid cancer. It starts in the C cells in the thyroid.
faulty genes, cause about a quarter (about 25%) of medullary thyroid cancers. These can run in families.
Medullary thyroid cancer can spread to lymph nodes and other parts of the body, such as the liver. lungs or bones.
This is the least common type of thyroid cancer. It grows faster than other types and is likely to spread. This means it can be more difficult to treat. When your doctor diagnoses you, this cancer has often already spread to other parts of the body.
Doctors usually diagnose anaplastic thyroid cancer in people older than 60. It is more common in women.
It is called undifferentiated because the cancer cells do not look like normal thyroid cells.
It is possible for a to develop in the thyroid gland. A primary thyroid lymphoma is a type of non-Hodgkin lymphoma. Treatment is similar to how doctors treat lymphoma.
Another rare type of thyroid cancer is sarcoma of the thyroid gland. You might have surgery, chemotherapy or radiotherapy to treat this type of cancer.
Go to information about treatment for your type of thyroid cancer
Last reviewed: 16 Sept 2026
Next review due: 16 Sept 2029
The type of thyroid cancer refers to the type of cell the cancer started in. The stage of a cancer tells you its size and whether it has spread.
Possible treatments include surgery, radiotherapy, targeted drugs and chemotherapy. What treatment you have depends on your type and stage of thyroid cancer.
Survival for thyroid cancer depends upon the type and stage of your thyroid cancer. Survival is generally very good for papillary and follicular thyroid cancers.
Thyroid cancer is when abnormal cells in the thyroid gland start to divide and grow in an uncontrolled way.
The thyroid is a small butterfly shaped gland that makes and releases hormones. It’s found at the front of your neck in the lowest part.
