Severe keratinizing squamous dysplasia of the oral cavity

by Jason Wasserman MD PhD FRCPC
July 16, 2024

Background:

Severe keratinizing squamous dysplasia is a precancerous condition characterized by abnormal and disorganized growth of squamous cells in the epithelium of the oral cavity. In this condition, the squamous cells show significant atypia (abnormalities in size, shape, and organization) and increased keratin production. The dysplasia is classified as severe when these cellular abnormalities extend through most of the thickness of the epithelium but do not yet invade the underlying connective tissue.

What parts of the oral cavity are typically involved in severe keratinizing squamous dysplasia?

Severe keratinizing squamous dysplasia can occur in various parts of the oral cavity, including:

• Tongue: Particularly the lateral borders and ventral surface.
• Floor of the mouth: An area under the tongue.
• Buccal mucosa: The inner lining of the cheeks.
• Gingiva: The gums.
• Hard palate: The roof of the mouth.
• Lips: The inner surface.

What are the symptoms of severe keratinizing squamous dysplasia?

The symptoms of severe keratinizing squamous dysplasia can be subtle and may include:

• White or red patches (leukoplakia or erythroplakia): These are areas of abnormal tissue that can be seen on the mucosal surfaces.
• Pain: Affected areas may be painful or sensitive.
• Thickened or rough areas: The surface may feel rough or thickened due to increased keratin production.
• Difficulty in chewing or swallowing: If the dysplasia is extensive, it may interfere with normal oral functions such as chewing and swallowing.
• Numbness: There may be a sensation of numbness in the affected areas.

What causes severe keratinizing squamous dysplasia?

Several factors can contribute to the development of severe keratinizing squamous dysplasia, including:

• Tobacco Use: Both smoking and smokeless tobacco are major risk factors.
• Alcohol consumption: Heavy alcohol use can exacerbate the effects of tobacco and independently increase risk.
• Chronic inflammatory conditions: Conditions like lichen planus can lead to chronic inflammation and increase the risk of dysplasia.
• Immune suppression/immune deficiency: Conditions or treatments that suppress the immune system can increase the risk of dysplastic changes due to reduced immune surveillance. Patients who have undergone an organ transplant and receive immune-suppressing medications are at particularly high risk.
• Betel nut chewing: Chewing betel nut (areca nut) is a significant risk factor, particularly in regions where this practice is common. Betel nut contains carcinogenic compounds that can lead to oral mucosal changes and dysplasia.

Is severe keratinizing squamous dysplasia associated with an increased risk of developing cancer of the oral cavity?

Yes, severe keratinizing squamous dysplasia is associated with a significantly increased risk of developing squamous cell carcinoma, a type of oral cavity cancer. The severity of the dysplasia correlates with the risk of progression to invasive cancer. Therefore, early detection and appropriate management of dysplastic lesions are crucial in preventing the development of oral cancer.

Microscopic features of severe keratinizing squamous dysplasia

Microscopically, severe keratinizing squamous dysplasia exhibits a disorganized epithelial structure with a loss of normal stratification and architecture of the squamous epithelium. The cells show marked abnormalities in size, shape, and nuclear features, including hyperchromasia (darkly staining nuclei), pleomorphism (variation in cell and nuclear size and shape), and an increased nuclear-to-cytoplasmic ratio. There is an elevated number of mitotic figures, including abnormal mitoses, indicating high cellular turnover. The atypical cells often extend through the full thickness of the epithelium but do not breach the basement membrane. The surface layer is often thickened and keratotic. Additionally, there may be chronic inflammation in the underlying connective tissue, which can accompany the dysplastic changes.

Margins

A margin is any tissue that the surgeon cuts to remove the abnormal tissue area from your body. The types of margins described in your report will depend on the area of the oral cavity involved and the type of surgery performed. Margins are usually only described in your report after the entire abnormal tissue area has been removed.

A negative margin means that dysplasia was not seen at any of the cut edges of the tissue. A margin is called positive when dysplasia is seen at the very edge of the cut tissue. A positive margin is associated with a higher risk that dysplasia will come back at the same site after treatment.

About this article

Doctors wrote this article to help you read and understand your pathology report. If you have any questions, please contact us.

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