Section Editor: Jason Wasserman MD PhD FRCPC
May 22, 2026
The oral cavity is the medical name for the mouth. It includes the lips, gums, tongue, the inside of the cheeks, the floor of the mouth, and the roof of the mouth (the hard palate). When tissue is removed from any of these areas, a pathologist examines it under a microscope and describes what they see in your pathology report.
This page brings together our guides to conditions found in the oral cavity. The articles are grouped by type to help you find the one that matches your diagnosis. Some conditions are cancerous, some are precancerous (not cancer, but a change that can increase the risk of cancer over time), and many are completely harmless. Select any article below to learn more.
Cancerous tumors
These diagnoses are cancers that start in the oral cavity. The articles explain how each cancer is diagnosed and what the details in your pathology report mean.
Squamous cell carcinoma is the most common type of cancer that starts in the mouth. This article explains how the diagnosis is made and what your pathology report describes, including tumor size, grade, and spread.
You may find this helpful if your report says squamous cell carcinoma of the lip, tongue, gums, or floor of the mouth.
Mucosal melanoma is a rare cancer that develops from pigment-producing cells in the lining of the mouth. This article explains how it is diagnosed and what your pathology report describes.
You may find this helpful if your report mentions mucosal melanoma or a dark-colored growth in the mouth.
Precancerous changes
These diagnoses describe abnormal cells that are not cancer but may carry an increased risk of becoming cancer over time. They are often watched closely or treated to prevent cancer from developing.
Oral epithelial dysplasia means the cells lining the mouth look abnormal under the microscope but are not cancer. This article explains what dysplasia means and why this diagnosis is important.
You may find this helpful if your report describes mild, moderate, or severe dysplasia of the mouth.
Squamous dysplasia describes abnormal changes in the flat, scale-like (squamous) cells of the lips, mouth, or tongue that are not yet cancer. This article explains how these changes are graded and followed over time.
You may find this helpful if your report mentions squamous dysplasia of the lip, mouth, or tongue.
Keratinizing squamous dysplasia
Keratinizing squamous dysplasia is a precancerous change in which the abnormal cells also produce extra keratin, a tough protein that can make the area look like a white patch. This article explains what this diagnosis means for you.
You may find this helpful if your report mentions keratinizing dysplasia or a white patch in the mouth.
HPV associated dysplasia is a precancerous change caused by the human papillomavirus (HPV), a common infection. This article explains how this type of dysplasia is identified and what it means for your health.
You may find this helpful if your report links your diagnosis to HPV or mentions p16 testing.
Squamous cell carcinoma in situ
Squamous cell carcinoma in situ is the earliest form of squamous cell carcinoma. The abnormal cells are still contained in the surface layer and have not spread into the deeper tissue. This article explains what this diagnosis means.
You may find this helpful if your report says carcinoma in situ or severe dysplasia of the lip, mouth, or tongue.
Noncancerous (benign) growths
These diagnoses are harmless growths in the oral cavity. They are not cancer and do not spread to other parts of the body, although they are sometimes removed if they cause discomfort.
A fibroma is a common, harmless growth made of connective tissue. It often forms in response to long-term irritation inside the mouth. This article explains what a fibroma is and how it is treated.
You may find this helpful if your report describes a fibroma or a firm bump on the inside of the cheek or lip.
A squamous papilloma is a small, noncancerous growth on the lining of the mouth that is often linked to the human papillomavirus (HPV). This article explains what it is and how it is treated.
You may find this helpful if your report describes a papilloma or a small wart-like growth in the mouth.
A mucocele is a harmless, fluid-filled swelling that forms when a small salivary gland is blocked or injured. This article explains how a mucocele develops and how it is treated.
You may find this helpful if your report mentions a mucocele or a soft bump on the lip or floor of the mouth.
An oral melanotic macule is a harmless, flat spot of extra pigment in the lining of the mouth. This article explains what causes it and why it is not cancer.
You may find this helpful if your report mentions a melanotic macule or a small dark spot in the mouth.
Inflammatory and infectious conditions
These diagnoses describe inflammation or infection in the lining of the mouth. They are not cancer, although a sample is sometimes taken to confirm the cause.
Acute mucositis is inflammation of the lining of the mouth. It is often caused by injury, infection, or cancer treatment. This article explains what the diagnosis means.
You may find this helpful if your report mentions acute mucositis, or you have mouth soreness after radiation or chemotherapy.
Lichenoid mucositis is a particular pattern of inflammation in the lining of the mouth. It can be caused by the immune system, medications, or dental materials. This article explains what it means and how it is managed.
You may find this helpful if your report mentions lichenoid mucositis or lichen planus of the mouth.
Hypertrophic candidiasis is a fungal infection of the mouth caused by Candida. It can create a thickened white patch that does not wipe away. This article explains how it is diagnosed and treated.
You may find this helpful if your report mentions candidiasis, a yeast or fungal infection, or a white patch in the mouth.
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