Human papilloma virus detection by immunohistochemistry on sinonasal papillomas and nasopharyngeal carcinomas: Report on 26 cases

Abstract

Background : Human papilloma virus (particularly HPV 6 and 11) has been documented in 20% to 76% of nasopharyngeal papillomas. HPV is also associated with 25% keratinizing nasopharyngeal squamous cell carcinoma detected by studies using techniques of immunopathology and by modern molecular biology. Objectives: To study the role of human papilloma virus as an etiological agent in sinonasal papillomas and nasopharyngeal carcinomas (NPCs) by immunohistochemistry (IHC). Materials and Methods: A total of 26 cases of neoplasms were studied for HPV antigen. Tumors were classified histopathologically by using Hematoxylin and Eosin-stained slides. Evidence of HPV infection like koilocytic changes and HPV antigens were noted down in all 26 cases. Results: There were 14 sinonasal papillomas, 7 each of fungiform and inverted types and 12 nasopharyngeal carcinomas. All cases of fungiform papillomas had either histological (koilocytes) or immunohisochemical evidence of HPV infection. 85.5% of inverted papillomas had evidence of HPV infection either in the form of koilocytes or in the form of positive immunohistochemistry or both. 50% of nasopharyngeal carcinomas had histological and immunohistochemical (either one or both) evidence of HPV infection. Conclusion: This study, unlike other studies, has found higher rate of HPV detection in both types of Schneiderian papillomas. Not many studies have been carried out on nasopharyngeal carcinomas. We have found evidence of HPV infection in 100% of moderately differentiated squamous cell carcinomas and 33.3% cases of poorly to undifferentiated cases of NPC.