Inverted papilloma (Schneiderian papilloma) with involvement of the oral cavity: report of an unusual case.

Inverted Schneiderian papilloma (ISP) is a neoplasm of epithelial lining origin which arises in the respiratory mucosa that lines the nasal cavity and paranasal sinuses. The inverted Schneiderian papilloma frequently appears as a unilateral lesion in the nasal septum and extends secondarily to the nasal and paranasal sinuses. This paper reports an unusual case of this pathology with involvement of the oral cavity in a 61-year-old white man. Clinical evaluation revealed a vegetating mass in the alveolar ridge of the right maxilla that had been present for approximately 4 months. After radiographic evaluation, involvement of the maxillary sinus was detected. Microscopic evaluation, in situ hybridization and immunohistochemical analysis of the specimen led to a diagnosis of ISP moderate dysplasia associated with HPV infection.