HPV-associated oral epithelial dysplasia

by Jason Wasserman MD PhD FRCPC
May 26, 2023

What is HPV-associated oral epithelial dysplasia?

HPV-associated oral epithelial dysplasia is a precancerous condition involving the tissue that covers the inside of the oral cavity. The oral cavity includes the lips, tongue, floor of mouth, gingiva (gums), buccal mucosa (inner cheeks), and hard palate. If left untreated, HPV-associated oral epithelial dysplasia can turn into a type of oral cavity cancer called squamous cell carcinoma.

Where does HPV-associated oral epithelial dysplasia start?

HPV-associated oral epithelial dysplasia starts from cells normally found in the epithelium, a thin layer of tissue that covers the inside surface of the oral cavity. The normal epithelium is made up of squamous cells (also known as keratinocytes) and basal cells.

What causes HPV-associated oral epithelial dysplasia?

HPV-associated oral epithelial dysplasia is caused by a long-standing infection of the cells on the inside of the oral cavity with human papillomavirus (HPV). Tobacco smoking and immunosuppression may increase the risk of developing HPV-associated oral epithelial dysplasia.

What are the symptoms of HPV-associated oral epithelial dysplasia?

Symptoms of HPV-associated oral epithelial dysplasia include a flat or raised growth that may appear red or white compared to the surrounding normal tissue.

Is HPV-associated oral epithelial dysplasia benign or malignant?

HPV-associated oral epithelial dysplasia is a benign (noncancerous) condition. However, if left untreated it can turn into a malignant (cancerous) tumour called squamous cell carcinoma.

How is HPV-associated oral epithelial dysplasia diagnosed?

The diagnosis of HPV-associated oral epithelial dysplasia can only be made after a sample of tissue is examined under the microscope by a pathologist.

What does HPV-associated oral epithelial dysplasia look like under the microscope?

When examined under the microscope, HPV-associated oral epithelial dysplasia is made up of large dark tumour cells that replace the healthy squamous cells normally found in the epithelium. Pathologists often describe these cells as basaloid because they look similar to the specialized basal cells found at the bottom of the epithelium. The tumour cells often have large atypical (abnormal) shaped nuclei with a high nuclear to cytoplasmic ratio (the nucleus takes up most of the cell). Dying tumour cells including karyorrhectic cells and apoptotic cells may also be seen. By definition, the tumour cells should be located entirely within the epithelium. For this reason, reports will often say that there was no evidence for invasion or spread of tumour cells into the tissue below the epithelium.

What is p16 and why is it important?

Cells infected with high-risk types of human papillomavirus (HPV) produce large amounts of a protein called p16. Your pathologist may perform a test called immunohistochemistry to look for p16 inside the abnormal cells. This will confirm the diagnosis of HPV-associated oral epithelial dysplasia and rule out other conditions that can look similar under the microscope. Almost all cases of HPV-associated oral epithelial dysplasia are positive or reactive for p16 which means that your pathologist saw the p16 protein in the abnormal cells.