Keratinizing Squamous Dysplasia of the Larynx: Understanding Your Pathology Report

Section Editor: Jason Wasserman MD PhD FRCPC
July 26, 2026

Keratinizing squamous dysplasia of the larynx is a precancerous change in the lining of the voice box. It develops in squamous cells, the flat cells that line the inside of the larynx, when they begin to grow and mature abnormally. What distinguishes this type is that the abnormal cells produce excess keratin, a tough protective protein normally made by skin rather than by the lining of the larynx. This is the most common form of dysplasia in the larynx.

Keratinizing squamous dysplasia is not cancer. The abnormal cells remain confined to the epithelium, the thin surface lining, and have not grown into the tissue beneath. That downward growth is what defines an invasive cancer, and its absence is what separates dysplasia from squamous cell carcinoma of the larynx. What the diagnosis does indicate is an increased risk that cancer could develop in that area over time, which is why the finding is taken seriously and followed carefully.

Dysplasia most often develops on the vocal cords, in the part of the larynx called the glottis, though it can occur anywhere in the voice box.

This article explains the findings you are likely to see on a pathology report for keratinizing squamous dysplasia of the larynx, what each one means, and why it matters for your care.

What causes keratinizing squamous dysplasia of the larynx?

Keratinizing squamous dysplasia of the larynx develops when the squamous cells lining the voice box are damaged repeatedly over a long period. Each round of injury and repair leaves behind small errors in the cells’ genetic material, and once enough accumulate in the genes controlling growth and maturation, the cells stop behaving normally. The excess keratin production is part of that disordered behavior. The main causes are:

Tobacco. By far the most important cause, and the one most strongly linked to this condition.
Alcohol. Heavy use raises risk on its own, and combining it with smoking raises risk considerably more than either alone.
Previous radiation to the neck. Radiation given years earlier for another condition can lead to changes in the treated area.
A weakened immune system. This includes long-term immune suppression after an organ transplant.

Long-term voice strain and exposure to workplace irritants such as dusts and fumes may also contribute. Because the whole lining of the larynx has usually been exposed to the same irritants, a new area of dysplasia can appear elsewhere in the voice box even after the first has been treated, which is one reason follow-up continues over the long term.

What are the symptoms of keratinizing squamous dysplasia of the larynx?

Because keratinizing squamous dysplasia usually develops on the vocal cords, the most common symptom by far is a change in the voice. Even a small area of abnormal lining on a vocal cord interferes with the way it vibrates. Symptoms include:

Hoarseness or a change in the voice, often the only symptom
A rough, strained, or breathy voice quality
Throat discomfort or a feeling of something in the throat
Difficulty swallowing, which is less common
Noisy breathing or shortness of breath, only with larger areas of change

Any change in the voice lasting more than two to three weeks should be assessed by an ear, nose, and throat specialist. The fact that hoarseness appears early is genuinely helpful here, because it often brings these changes to attention while they are still limited and treatable.

How is the diagnosis made?

Keratinizing squamous dysplasia of the larynx is diagnosed only when tissue from the abnormal area is examined under the microscope by a pathologist. A specialist may see a white or thickened patch on the vocal cord when examining the larynx, but the appearance alone cannot establish the diagnosis or the grade, and it cannot determine whether an invasive cancer is present.

The tissue is obtained by biopsy during a procedure called microlaryngoscopy, in which a thin scope is passed through the mouth under general anesthetic so the surgeon can see the vocal cords directly and remove the abnormal area or take a sample.

Under the microscope, the pathologist assesses how abnormal the cells look, how disorganized the lining is, and how far up through its thickness the changes extend, then combines this into a grade. Just as importantly, the pathologist confirms that the abnormal cells have not broken through the base of the lining into the tissue below. That downward growth is called invasion, and it is what would change the diagnosis to invasive squamous cell carcinoma.

Your report may include descriptive terms alongside the diagnosis. Hyperkeratosis means a thickened layer of keratin on the surface, and it is what usually makes the area look white. These terms describe what the pathologist saw and accompany the diagnosis rather than adding to it. The grade remains the finding that matters most.

One limitation of a small biopsy is worth knowing. It samples only part of the abnormal area, and the region sampled is not always the most abnormal one. This is a reason the whole area is often removed rather than just sampled, so it can be examined completely, and an invasive cancer ruled out across the entire lesion.

How is keratinizing squamous dysplasia of the larynx graded?

The grade is the most important part of your report, because it is the strongest predictor of whether the abnormal area will progress to cancer. Two grading systems are in use for the larynx, and your report may show either, so both are explained here.

The two-tier system. This is the system currently recommended by the World Health Organization for the larynx, and it is increasingly what laboratories use.

Low-grade dysplasia. The abnormal changes are limited to the lower part of the lining, the cells show at most minor abnormalities, and the normal orderly maturation from bottom to surface is largely preserved.
High-grade dysplasia. The cells show clearly abnormal features extending from the lower half through to the full thickness of the lining, with loss of the normal orderly maturation.

The three-tier system. Some laboratories still report dysplasia as mild, moderate, or severe, based on how far up through the thickness of the lining the changes extend: the lower third for mild, the middle third for moderate, and the upper third for severe.

How the two systems relate, and why it matters. This is the point most worth understanding. When the two-tier system is applied to the larynx, mild dysplasia corresponds to low-grade, while both moderate and severe dysplasia are grouped together as high-grade. This differs from the oral cavity, where moderate dysplasia sits ambiguously between the two categories. In the larynx, the evidence showed that moderate and severe dysplasia carry a similar risk of progressing to cancer, well above that of mild dysplasia, so they were combined.

The practical consequence is that if your report says moderate dysplasia of the larynx, it is generally managed as a high-grade change rather than as something intermediate. If you are unsure which category your result falls into, this is a good question for your doctor.

Carcinoma in situ. Some reports use squamous cell carcinoma in situ as a separate, highest category. The word “carcinoma” understandably causes alarm, but carcinoma in situ means the abnormal cells still sit entirely within the surface lining and have not invaded. It is not an invasive cancer.

One further point is worth knowing, because patients sometimes seek second opinions and find the grade has changed. Grading dysplasia is a judgment rather than a measurement, and agreement between pathologists is only moderate. A change in grade on review is common and does not mean an error was made. Simplifying to two tiers was intended partly to improve this consistency.

Surgical margins

When an area of dysplasia is removed completely rather than only sampled, the report may describe the margins, the cut edges of the tissue removed. The pathologist examines whether abnormal cells reach any edge.

Negative (clear) margin. No dysplasia at the cut edge. The abnormal area appears to have been completely removed.
Positive (involved) margin. Dysplasia reaches the cut edge, meaning some abnormal tissue may remain. Depending on the grade, your doctor may discuss removing more tissue or monitoring the area closely.
Cannot be assessed. The tissue was fragmented, or the edges were cauterized during removal, which is common with laser procedures. This does not mean the procedure was inadequate, but it makes careful follow-up more important.

Margins in dysplasia are interpreted differently from margins in cancer surgery. Dysplasia often extends beyond what can be seen through the scope, and the surrounding lining may already carry damage while appearing normal. A negative margin therefore means the abnormal-looking tissue was removed, not that the risk has been eliminated, which is why surveillance continues regardless of what the margins show. In the larynx there is a further consideration: the surgeon works to remove the abnormal area while preserving as much normal vocal cord as possible, because taking too much tissue affects the voice.

What is the risk that keratinizing squamous dysplasia will turn into cancer?

Keratinizing squamous dysplasia of the larynx is a precancerous change, and most people who have it do not go on to develop cancer. The risk depends heavily on the grade.

Low-grade dysplasia, corresponding to mild dysplasia in the older system, carries a low risk, generally reported in the range of about 5 to 10%. High-grade dysplasia, which includes both moderate and severe dysplasia, carries a substantially higher risk. Reported rates vary widely between studies, from roughly 15% to over 40%, reflecting differences in how the lesions were classified and how long patients were followed. What is consistent across studies is the size of the gap between the two grades.

Factors that increase risk include a higher grade, continued smoking, and dysplasia that returns after treatment or appears at more than one site. Of these, continued tobacco use is the one that can be changed, and stopping is the single most effective step available.

These figures are averages drawn from groups of patients followed over many years. They describe patterns rather than predictions for any one person, and your own risk is best discussed with the specialist who can see your larynx and knows your history.

What happens after the diagnosis?

Treatment depends on the grade, how much of the larynx is involved, and whether the abnormal area was completely removed. Care is usually led by an ear, nose, and throat surgeon.

For low-grade dysplasia, the abnormal area is often already removed at the time of the diagnostic procedure, and regular examination of the larynx may be all that follows. For high-grade dysplasia, including moderate and severe changes, complete removal is generally recommended, most often using a laser through a scope passed into the throat. Removal serves two purposes: it takes out the abnormal tissue, and it allows the whole area to be examined so that an unsuspected early cancer is not missed. Radiation is occasionally considered for extensive or repeatedly recurring changes.

Two things matter alongside any procedure. The first is stopping smoking and reducing alcohol, which removes the ongoing damage driving the process. Some lower-grade changes improve once these exposures stop, and support for quitting is a standard part of care. The second is regular follow-up examination of the larynx, since dysplasia can return at the same site or appear elsewhere in the voice box. Follow-up generally continues for years rather than for a fixed period. Voice therapy with a speech-language pathologist may also be offered, particularly if the voice has changed after a procedure on the vocal cords.

Questions to ask your doctor

What grade of dysplasia was found, and did my report use the two-tier or the three-tier system?
If my report says moderate dysplasia, is that being treated as high-grade?
Where in my larynx is the abnormal area, and how much of it is involved?
Was the whole area removed, or was only a sample taken?
If it was removed, were the margins clear?
Was there any sign of invasive cancer?
Given my grade, what is my risk of developing cancer?
Do I need further treatment, or can this be monitored?
How often will my larynx be examined, and for how long?
What help is available to me for stopping smoking?
Will my voice be affected, and would voice therapy help?
What changes should prompt me to call before my next visit?