by Jason Wasserman MD PhD FRCPC
July 13, 2022
Keratinizing squamous dysplasia is a pre-cancerous disease that starts from specialized squamous cells that cover the inside surface of the oral cavity. This area includes the lips, tongue, floor of mouth, cheeks, and hard palate. Keratinizing squamous dysplasia is considered a pre-cancerous disease because it can over time turn into a type of cancer called squamous cell carcinoma.
No. Keratinizing squamous dysplasia in the oral cavity is not cancer. It is, however, a precancerous condition that can turn into a type of cancer called squamous cell carcinoma over time.
The most common cause of keratinizing squamous dysplasia in the oral cavity is smoking. Other causes include excessive alcohol consumption, immune suppression, and inflammatory conditions such as lichen planus.
The diagnosis of keratinizing squamous dysplasia is usually made after a small sample of tissue is removed in a procedure called a biopsy. The biopsy is usually performed because you or your doctor saw an abnormal-looking area of tissue within your oral cavity. Your pathology report will probably say what part of the oral cavity was sampled in the biopsy. The diagnosis can also be made after a larger piece of tissue is removed in a procedure called an excision.
This picture shows an example of keratinizing squamous dysplasia.
Keratinizing squamous dysplasia in the oral cavity is divided into grades by comparing the abnormal cells in the area of disease to the healthy squamous cells normally found in the oral cavity. There are two different systems for dividing keratinizing squamous dysplasia into grades. One system divides the disease into two grades – low grade and high grade. The other system divides the disease into three grades – mild, moderate, and severe. When the three-level system is used, moderate and severe dysplasia are often grouped together under the category “high grade”. For example, if a pathology report says “negative for high grade dysplasia”, that means that the pathologist did not see any moderate or severe dysplasia in the tissue sample.
The grade of keratinizing squamous dysplasia is very important because it is related to the risk of developing a type of cancer called squamous cell carcinoma in the future. Low grade or mild keratinizing squamous dysplasia is associated with the lowest risk of developing cancer and those who do develop cancer tend to develop it after many years. Moderate and severe or high grade keratinizing squamous dysplasia is associated with the highest risk of developing cancer and patients are typically offered treatment to remove the disease before it progresses to cancer.
A margin is any tissue that was cut by the surgeon in order to remove the abnormal area of tissue 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 area of tissue has been removed.
A negative margin means that dysplasia was not seen at any of the cut edges of 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.