Squamous papilloma of the oral cavity

What is a squamous papilloma?

Squamous papilloma is a common type of non-cancerous growth. It starts from the epithelium lining the inside of the mouth and is made up of squamous cells that connect together to form long finger-like projections of tissue. Pathologists call these finger-like projections papilla and the pattern of growth papillary. Most start on the tongue, inner cheek (buccal mucosa), or roof of the mouth (hard or soft palate) although they can start anywhere in the mouth.

The oral cavity

The oral cavity is the beginning of the aerodigestive tract. The oral cavity starts at the lips and ends where the mouth meets the throat. The oral cavity is made up of multiple parts including the lips, tongue, floor of mouth, gingiva, buccal mucosa, hard palate, and retromolar trigone.

The inner surface of the oral cavity is covered by specialized squamous cells. that form a barrier called the epithelium. The tissue below the epithelium is called the stroma. Pathologists use the word mucosa to describe tissue that includes both the epithelium and the stroma.

What causes a squamous papilloma?

Most squamous papillomas in the mouth are caused by infection of the squamous cells by human papillomavirus (HPV). There are many types of human papillomavirus and the types that cause squamous papilloma are called low risk because they are not associated with an increased risk of developing cancer.

Some squamous papillomas are probably caused by trauma such as accidental biting of the tongue, cheeks, or lips. Poorly fitting dentures or other oral devices can also cause this type of growth.

How do pathologists make this diagnosis?

The diagnosis is made after the growth is removed and sent to a pathologist for examination under a microscope. Sometimes only a small sample of the papilloma will be removed in a procedure called a biopsy. In these situations, your doctor may suggest a second procedure to remove the remainder of the growth.

by Jason Wasserman MD PhD FCPCP (updated June 1, 2021)