Laryngeal Papillomatosis: Molecular, Ultrastructural and Clinical Evaluation

Our study was designed to correlate the prevalence of human papilloma viruses (HPV) types 6 and 11 in laryngeal papillomatosis specimens using PCR to the clinical and pathological characteristics of these patients as a trial to evaluate the usefulness of HPV typing in identifying which patients are at a higher risk for more frequently recurring aggressive disease or future malignant. This study was conducted on 36 adult patients who were identified clinically and histopathologically as laryngeal papilloma. An index of the number of procedures (laryngoscopy and carbon dioxide laser ablation) needed per year for each patient was calculated to assess the frequency of recurrence and disease aggressiveness. They were subjected to the detection of HPV6 and 11 DNA by PCR and electon microscopic examination of biopsies that were taken from laryngeal papillomas and non diseased sites as controls. We found that all papillomas (100%) were positive for HPV, among them the positive rate of either HPV6 or HPV1 1 was 25% (9/36) and 41.7% (15/36) respectively, the positive rate of mixed types of HPV6 + 11 was 33.3% (12/36). Percentage of Patients needed 3 Pr/y were significantly increased (p 0.05 0.01) in cases with mixed infection of both HPV6+11 in comparison to those infected with HPV 11 or HPV6 respectively and in HPV 11 infected cases in comparison to those infected with HPV 6 (p 0.05). Percentage of cases revealed dysplastic features (cellular atypia, invasion, keratinization and necrosis) were significantly increased (p 0.05 0.01) in mixed infection of both HPV6+11 in comparison to those infected with HPV 11 or HPV6 respectively and in HPV11 infected cases in comparison to those infected with HPV6 (p 0.05). Correlation study revealed direct correlation between percentage of patients needed 3 Pr/y and the appearance of dysplastic features. Our findings suggest that viral typing is one marker that may be useful to identify patients at a higher risk for aggressive disease and, possibly, to malignant potential but more studies with a larger number of cases are needed to assess their diagnostic and prognostic value.