By Jason Wasserman MD PhD FRCPC
February 7, 2023
High grade dysplasia is a precancerous condition in the larynx. If not treated, high grade dysplasia can change into a type of laryngeal cancer called squamous cell carcinoma over time.
High grade dysplasia starts from specialized squamous cells that cover the inside surface of the larynx. High grade dysplasia can start anywhere in the larynx although the most common site is the glottis which includes the vocal cords. Less common sites include the supraglottis and subglottis.
No. High grade dysplasia is not a type of cancer. It is, however, a precancerous condition that can change into a type of cancer called squamous cell carcinoma over time if not treated.
High grade dysplasia of the larynx is not considered malignant because the abnormal cells are not able to spread to other parts of the body.
No. Because high grade dysplasia is a non-invasive precancerous condition, the abnormal cells are unable to spread to other parts of the body.
Yes. High grade dysplasia and severe squamous dysplasia in the larynx are two different names used to describe the same condition. High grade dysplasia is part of a two-tier grading system that divides dysplasia in the larynx into low grade and high grade. In contrast, severe squamous dysplasia is part of a three-tier grading system that divides dysplasia into mild, moderate, and severe. When the two systems are compared, severe dysplasia and high grade dysplasia are considered equivalent.
The most common cause of high grade dysplasia in the larynx is smoking. Other causes include excessive alcohol consumption, immune suppression, and prior radiation to the neck.
The diagnosis of high grade dysplasia in the larynx is usually made after a small sample of tissue is removed in a procedure called a biopsy. The biopsy is usually performed because your doctor saw an abnormal-looking area of tissue during an examination of your larynx. Your pathology report will probably say what part of the larynx was sampled in the biopsy.
When examined under the microscope, the cells in high grade dysplasia are larger and darker than the healthy squamous cells normally found in the larynx. Pathologists use the word hyperchromatic to describe cells that are darker than normal cells. An abnormal pattern of maturation called “keratinization” may also be seen. Cells that show keratinization contain large amounts of a protein called keratin which is abnormal in the larynx.