Stages and types of thyroid cancer
There are a number of different types of thyroid cancer. This includes:
papillary thyroid cancer
follicular thyroid cancer
oncocytic cell (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 use a system for classifying thyroid tumours into types. This system is regularly updated. The latest 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 if you want more information about your diagnosis.
To diagnose thyroid cancer, a specialist doctor (pathologist) examines a sample of thyroid cells under the microscope. They look at several factors to group (classify) 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 (Hurthle cell) thyroid cancer
A small number of thyroid cancers start in the C cells. These are called 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
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 gene changes in the cancer cells. These tests are also called biomarker or molecular studies. The results of these tests help the doctors work out your type of thyroid cancer.
About 90 out of 100 thyroid cancers (about 90%) are differentiated cancers that start in follicular cells. 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 lymph nodes 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, such as the lungs or bones.
Oncocytic thyroid cancer is a rare type of thyroid cancer, also called Hurthle cell thyroid cancer. It used to be grouped with follicular thyroid cancers as it shares some similarities.
Oncocytic cells look different to follicular cells. The cells are also called oxyphilic cells, so this cancer is sometimes called oxyphil cell cancer. Oncocytic tumours can be non cancerous (benign) or cancerous. Benign tumours are called oncocytic adenomas. Oncocytic thyroid cancer can sometimes spread to lymph nodes or to other parts of the body.
Oncocytic thyroid cancer is most often diagnosed in people older than 40, and is more common in women.
The pathologist looks at the thyroid cancer under the microscope to find out the 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)
the cancer contains dying tissue (necrosis)
Doctors call these thyroid cancers follicular derived thyroid cancer, high grade. Depending on how abnormal the cells look, these high grade cancers are:
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.
They are often diagnosed at a later stage than other types of thyroid cancer. Some treatments might not work as well and you might need more intense treatment. The doctors might follow you more closely when you finish treatment in case the cancer comes back.
The cells in poorly 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.
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.
This is the least common and most serious thyroid cancer.
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.
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.
Go to information about treatment for your type of thyroid cancer
Last reviewed: 20 Oct 2023
Next review due: 20 Oct 2026
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.
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