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Types and grades

Most mouth and oropharyngeal cancers are squamous cell cancers. But there are less common types. Read about the different types and grades. 

Squamous cell cancers of the mouth and oropharynx

More than 90 out of 100 (90%) mouth and oropharyngeal cancers are squamous cell carcinomas. Squamous cells are the flat, skin like cells covering the inside of the mouth, nose, larynx and throat. Carcinoma means cancer. Squamous cell carcinoma is cancer starting in the squamous cells.

Verrucous carcinoma is an unusual type of squamous cell carcinoma. It spreads to other parts of the body but can grow very deeply into surrounding tissues.  

Other types of mouth and oropharyngeal cancer

About 10 out of 100 (10%) mouth and oropharyngeal cancers are one of the following types. 

Salivary gland cancer 

There are minor salivary glands throughout the lining of the mouth and oropharynx. It is more common for a lump in this area to be non cancerous (benign). But cancers can develop in these glands. They are mostly a type of cancer called adenocarcinoma. Adenocarcinomas are type of cancer that start in glandular tissue.

Adenoid cystic tumour 

This is a rare type of tumour and can develop from glandular tissue in the salivary glands or the mouth. The parotid gland is the most common place to find this type of cancer. About 25 out of 100 (25%) tumours found in the parotid gland are cancer.


Lymphomas are cancers that start from cells in the lymphatic system. The base of the tongue and tonsils are made up of lymph tissue that can develop into cancer. There are also many lymph nodes in the neck. Painless swelling of a lymph node is the most common sign of lymphoma. Treatment for lymphoma will be very different to treatment for mouth or orpharyngeal cancer. 


Melanomas develop from the pigment producing cells that give skin its colour. Melanomas of the head and neck can occur anywhere on the skin or inside the nose or mouth (oral cavity). If you have a melanoma of the mouth or lip, the information about radiotherapy or surgery for mouth and oropharyngeal cancer will be useful. 

Non cancerous growths in the mouth and oropharynx

A growth or tumour is not always a cancer. Non cancerous growths are called benign.

The main difference between a cancer and a benign tumour is that a cancer can spread, while a benign tumour does not. Some mouth and oropharyngeal tumours are benign and so don't spread to other parts of the body.

Precancerous changes in the mouth and oropharynx

Two different medical conditions can cause abnormal areas in the mouth or throat. They are harmless to begin with but if left untreated can turn into a cancer in a small number of people. Doctors call these conditions precancerous. They are:

  • leukoplakia 
  • erythroplakia

Leukoplakia and erythoplakia

Leukoplakia is a white patch in the mouth. Erythroplakia is a red area in the mouth that bleeds easily. These white or red patches might be harmless. But they can also be precancerous and contain abnormal cells. These abnormal cells are called dysplasia. Untreated, these might go on to develop into cancer.

Your doctor takes a sample of the cells (biopsy) to find out what the patches are. 

Only about 5 out of every 100 people (5%) diagnosed with leukoplakia have cancerous or precancerous changes. But about 50 out of 100 (50%) erythroplakia lesions can become cancerous. 

Risks and causes

The most common causes of leukoplakia and erythroplakia are smoking and chewing tobacco. It can also develop if you have badly fitting dentures that constantly rub your gums, or the inside of your mouth or tongue.

It is important to get regular dental check ups if you have dentures. And giving up alcohol or stopping smoking may help reduce the white patches.


You might need treatment if stopping smoking and alcohol doesn't help, or if the lesion shows early signs of cancer. If you have dyplasia, there is a risk that you might develop mouth cancer. If your doctor removes the dysplasia your risk of mouth cancer usually disappears. Your doctor may remove the patches using a laser or scalpel. 

Researchers are trying a group of drugs called retinoids on leukoplakia. Retinoids are made from vitamin A. They are used to treat severe acne and other skin conditions. They can be effective in treating leukoplakia but they can have serious side effects. 

Beta carotene is an anti oxident that is converted to vitamin A in your body. Small research studies have shown that it might be an effective treatment for leukoplakia patches. The treatment is still experimental and it is not generally prescribed on the NHS. 

You are at higher risk of leukoplakia and erythroplakia coming back if you smoke. Your doctor will strongly advise you give up smoking.

Grades of mouth cancer

The specialist doctor (pathologist) examines the cancer cells under a microscope to find out the grade. The grade of a cancer tells you how much the cancer cells look like normal cells. This gives your doctor an idea of how the cancer might behave and what treatment you need. 

There are 4 grades of mouth and oropharyngeal cancer:

  • grade 1 (low grade) look very much like normal mouth or oropharyngeal cells
  • grade 2 (intermediate grade) look slightly different to normal mouth or oropharyngeal cells
  • grade 3 (high grade) look very abnormal and not much like normal cells 
  • grade 4 (high grade) look very different to normal mouth or oropharyngeal cells

Differentiation means how developed or mature a cell is. Doctors might describe cancer as poorly or well differentiated. 

So doctors may describe grade 1 cancer as well differentiated. Grade 2 cancer cells are moderately differentiated. Grade 3 cancer cells are poorly differentiated. And grade 4 cells are undifferentiated. 

Last reviewed: 
02 Oct 2014
  • Cancer: Principles and practice of oncology (9th edition)
    VT De Vita, S Hellman and SA Rosenberg
    Lippincott, Williams and Wilkins, 2011

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