Bilateral Inverted Papilloma of Maxillary and Ethmoid Sinuses with Multiple Recurrences

Inverted papilloma (IP) or Shneiderian papilloma is a benign neoplasm of the sinonasal cavity that is hallmarked by its locally invasiveness, tendency for recurrence and malignant transformation. They arise from the ectodermally derived Scheiderian mucosa that lines the nasal cavity and paranasal sinuses. Predominantly observed in males in their fifth and sixth decade of life, it has an annual incidence of 0.6-1.5 per 100,000. Mostly IP occur unilaterally and the incidence of bilateral synchronous inverted papilloma is 4-5% [1,2]. The most common site of occurrence of IP is at the lateral nasal wall and maxillary sinus, followed by ethmoid air cells and nasal septum. Less commonly these can arise at the sphenoid and frontal sinuses. Bilateral presentation can be due to synchronous multicentric growth with no communication or unilateral disease spreading to the contralateral side through septal perforation [3]. Often it is difficult to determine the disease origin due to the involvement of multiple sites.