Precancerous lesions of laryngeal cancer

Normal laryngeal epithelium develops from hyperplasia to laryngeal cancer, generally through several stages such as hyperplastic keratinization, atypical hyperplasia, carcinoma in situ and micro-invasive carcinoma. Foreign data show that about 1/5 of laryngeal cancer patients have been found to have laryngeal mucosal changes at least 1 year before diagnosis. Most scholars believe that laryngeal cancer often occurs on the basis of existing laryngeal mucosal lesions.

Precancerous lesions refer to diseases that are more likely to become cancerous than normal mucosa, including laryngeal keratosis, chronic hypertrophic laryngitis and laryngeal papilloma.

1. Laryngeal keratosis

It includes laryngeal leukoplakia, pachyderma, and hyperkeratosis. The main symptom is hoarseness. The lesions are mostly seen in the vocal cords. The pathological changes are caused by the epithelial hyperplasia and accumulation of keratinized substances in the mucosal layer, forming white plaques, thickening of the mucosa, hyperplasia of epithelial cells, irregular cell size and shape, inflammatory changes under the epithelium but an intact basement membrane, and sometimes irregular protrusions of epithelial cells into the mucosal stroma. Clinically, it is divided into two types: flat type and verrucous type. Laryngeal keratosis is mostly treated conservatively or with vocal cord peeling. If accompanied by severe atypical hyperplasia, microscopic laser surgery or partial laryngectomy can be performed.

2. Chronic hypertrophic laryngitis

Chronic hypertrophic laryngitis refers to a chronic inflammation of the laryngeal mucosa caused by common bacterial infection or improper use of the voice, which may affect the submucosal layer and intrinsic laryngeal muscles. The main symptom is hoarseness. Under laryngoscopy, extensive thickening of the laryngeal mucosa can be seen, especially in the arytenoid area, which may appear nodular or polyp-like. Excessive hyperplasia of tissue can be removed under laryngoscopy or cauterized with laser.

3. Laryngeal papilloma

It is the most common benign tumor of the larynx. It is formed by the proliferation of the stratified flat tumor, contains a core composed of connective tissue and blood vessels, and does not infiltrate the submucosal membrane. It is generally believed to be caused by human papillomavirus (HPV) infection. Adult-type laryngeal papilloma, especially in the elderly, is prone to malignant transformation. Treatment is mostly surgical resection, with laser surgery being the best. Radiotherapy can induce malignant transformation, so radiotherapy is not suitable.