Squamous papilloma of the oral cavity

This article will help you read and understand your pathology report for squamous papilloma of the oral cavity.

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

Quick facts:

• Squamous papilloma is a non-cancerous growth that develops on the inside of the mouth.
• It is made up of specialized squamous cells that connect together to form long finger-like projections of tissue called papilla.
• Most squamous papillomas are caused by infection of the cells inside the mouth by human papillomavirus (HPV).

The oral cavity

The oral cavity is the beginning of the aerodigestive tract. It is used for both breathing and taking in food. The oral cavity is a complex area of the body that is made up of many parts.

Parts of the oral cavity

• Lips – The soft inner surface of the lips are part of the oral cavity. The outer surface of the lips are covered by skin and are not considered part of the oral cavity.
• Tongue – The part of the tongue that you can see when you look in your mouth is part of the oral cavity. The very back of the tongue (the part you cannot see) is part of another area of the body called the oropharynx.
• Floor of mouth – The floor of mouth is the soft tissue underneath your tongue.
• Cheeks – The inner surface of the cheeks are part of the oral cavity. The inner cheeks are also called the buccal mucosa.
• Gums – The gums are the tissue that surround and hold the teeth. The gums are also called gingiva.
• Roof of mouth – This is the top of your mouth. Only the hard part of the roof is part of the oral cavity. The soft part of the roof at the very back of your mouth near your throat is called the soft palate and it is part of another area of the body called the oropharynx.
• Retromolar trigone – This is a small triangle-shaped area of tissue behind the last tooth on the bottom of your mouth.

All of the parts of the oral cavity are lined by specialized squamous cells that create a barrier called the epithelium. The tissue below the epithelium is called the stroma. The epithelium is separated from the stroma by a thin strip of tissue called the basement membrane. Pathologists use the word mucosa to describe all of the tissue above the stroma.

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.

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.