Unusual anatomic presentations of inverting papilloma.

Due to their tendency to recur, and a potential for malignancy, inverting papillomas of the nasal cavity and paranasal sinuses pose a challenge to the head and neck surgeon. Although the majority of these benign neoplasms arise from the lateral nasal wall, middle meatus, and ethmoid complex, they occasionally originate from atypical areas in which Schneiderian membrane is present. Four unusual anatomical presentations of inverting papilloma are presented and discussed.