Human Papillomavirus-Driven Squamous Lesions: High-Risk Genotype Found in Conjunctival Papillomas, Dysplasia, and Carcinoma

Background: Human papillomavirus (HPV) is a causative agent for intraepithelial squamous neoplasms, particularly on mucosal surfaces. HPV has a well-established association with squamous cell carcinoma (SCC) of the oropharynx and genital tract, and recent studies suggest a potential role in ocular and periocular squamous neoplasms. Multiple high-risk HPV genotypes are associated with histologically similar squamous neoplasms, and some HPV genotypes have been differentially associated with high- or low-grade lesions. Methods: Squamous lesions were screened with immunohistochemical markers p16 and Ki-67 to compare expression in conjunctival papillomas (n = 21) to papillomas with high-grade dysplasia, SCC in situ, and invasive SCC (n = 40). Polymerase chain reaction was performed using the Roche COBAS HPV assay to identify the 14 most common high-risk HPV genotypes. Results: Compared with squamous papillomas, the lesions showing high-grade dysplasia or worse expressed p16 with greater intensity and in a greater percentage of the lesion. A trend toward mild Ki-67 expression in papillomas versus marked Ki-67 expression in high-grade squamous lesions was also observed. HPV-16 was present in 7 of the SCC in situ and invasive SCC lesions but none of the papillomas. Conclusions: HPV may have an important role in squamous lesions of the conjunctiva. In addition to positive polymerase chain reaction results, strong and diffuse p16 expression with marked Ki-67 is strongly suggestive of an HPV-driven lesion.