Pathological mechanisms of laryngeal papillomatosis based on laryngeal epithelial characteristics

OBJECTIVES: Human papillomavirus (HPV) infects basal cells of the stratified squamous epithelium through micro epithelial trauma. However, laryngeal papillomatosis commonly appears in any site on the laryngeal mucosa not covered by stratified squamous epithelium. The purpose of this study is to clarify pathological mechanisms of laryngeal papillomatosis based on the characteristics of the laryngeal epithelium. STUDY DESIGN: Morphological and immunohistochemical study. METHODS: Larynges from one newborn and two adults were used. Morphological differences in the laryngeal squamo‐ciliary junction (lSCJ) were compared to those in the cervical squamo‐columnar junction (cSCJ) in a resected cervix uterus. Morphological characteristics of laryngeal epithelial distribution were also compared between the newborn and adult larynges. Immunohistochemical evaluations were performed using p63 (an epithelial stem‐cell marker) and integrin‐α6 (a cellular HPV receptor). RESULTS: Morphological differences were noted between the lSCJ and the cSCJ. The lSCJ was present in the adult, but not the newborn supraglottis. Goblet cells in the pseudostratified ciliated columnar epithelium were also found in the adult but not the newborn larynx. In addition, basal cells of the stratified squamous epithelium as well as the pseudostratified ciliated columnar epithelium expressed p63 and integrin‐α6 in both newborn and adult larynges. CONCLUSIONS: HPV can infect any immature laryngeal epithelium with or without the lSCJ. Squamous metaplasia of pseudostratified ciliated columnar epithelium with a latent HPV infection can also cause tumorigenesis. LEVEL OF EVIDENCE: N/A