Sections demonstrate two distinct histologic neoplasms: an inverted papilloma and a coexisting verrucous carcinoma. Microscopically, the inverted papilloma comprises less than 10% of the tumor mass. Inverted papillomas are not infrequently associated with malignant tumors, primarily squamous cell carcinoma, and in some instances malignant transformation in an inverted papilloma to carcinoma may be observed. In this case, there is no transitional zone in the sections examined to suggest that the verrucous carcinoma is arising directly from the inverted papilloma. Although immunoperoxidase stains for human papillomavirus antigens are negative in both components of the tumor mass, inverted papillomas and verrucous carcinomas have been associated with human papillomavirus infection.
Contributed by Jeff Nine, M.D.