Ultrastructural features of the adult laryngeal papilloma

Expanded Basal Compartment and Disrupted Barrier in Vocal Fold Epithelium Infected with Mouse Papillomavirus MmuPV1

Laryngeal infection with low-risk human papillomaviruses can cause recurrent respiratory papillomatosis (RRP), a disease with severe effects on vocal fold epithelium resulting in impaired voice function and communication. RRP research has been stymied by limited preclinical models. We recently reported a murine model of laryngeal MmuPV1 infection and disease in immunodeficient mice. In the current study, we compare quantitative and qualitative measures of epithelial proliferation, apoptosis, differentiation, and barrier between mice with MmuPV1-induced disease of the larynx and surrounding tissues and equal numbers of uninfected controls. Findings supported our hypothesis that laryngeal MmuPV1 infection recapitulates many features of RRP. Like RRP, MmuPV1 increased proliferation in infected vocal fold epithelium, expanded the basal compartment of cells, decreased differentiated cells, and altered cell–cell junctions and basement membrane. Effects of MmuPV1 on apoptosis were equivocal, as with RRP. Barrier markers resembled human neoplastic disease in severe MmuPV1-induced disease. We conclude that MmuPV1 infection of the mouse larynx provides a useful, if imperfect, preclinical model for RRP that will facilitate further study and treatment development for this intractable and devastating disease.

Laryngeal papillomas with adult onset. An epidemiological study from the Copenhagen region

All patients treated for laryngeal papillomas with adult onset in the Copenhagen region during a 4-year period were identified for this epidemiological study. The incidence was 0.8/100,000 among the population at risk and the prevalence was 2.3/100,000. It is concluded that papillomas with juvenile and adult onset are one and the same disease and that single papillomas versus multiple papillomas cannot be considered different entities. As is the case with juvenile laryngeal papillomas, the prognosis is good and the morbidity low in most cases of adult onset papillomas, but malignant degeneration must be considered a risk factor.