A case of inverted papilloma of the maxillary sinus with extension into the oral cavity after repeated recurrence

The patient was a 48-year-old man with an unusual papillary tumor of maxillary sinus origin extending from the left premolar to the right molar region of the maxilla. Clinical examination suggested that the tumor was malignant, because of repeated recurrence and extensive bone destruction. The tumor was removed en bloc after chemotherapy with pepleomycin, which was ineffective. Histopathological examination revealed an inverted papilloma with moderate atypism.Immunohistochemically, p53, Ki-67, and PCNA were positive in tumor cells. The labeling indices of these markers were between those of leukoplakia and squamous cell carcinoma. This is the first reported case of inverted papilloma of the maxillary sinus with extension into the oral cavity.