Inverted Sinonasal Papilloma: Update and Literature Review

Inverted sinonasal papilloma is a benign neoplasm that usually affects the intra-nasal cavity and adjacent paranasal sinuses. Inverted papillomas have three unique features that distinguishes them from other sinonasal tumors including; a propensity for local destructive growth, a high rate of recurrence and risk of malignant transformation. The reported yearly incidence is about 0.6 to 1.5 cases per 100,000 people per year and they usually account for 0.5% to 4% of all nasal tumors. They occur at the following locations; both lateral nasal walls, ethmoidal cells, maxillary sinus, the frontal sinus, sphenoid sinuses and the nasal septum in decreasing order. It occurs most commonly in the fifth and sixth decades of life with a male-to-female ratio of 2-3:1. Inverted papilloma can arise from the entire Schneiderian membrane and molecular genetics have confirmed that it is an actual neoplasm that arises from a single progenitor cell. Most cases are diagnosed from clinical history and thorough physical examination. However, complete removal of all affected tissue with thorough histopathological evaluation is recommended to ensure a correct diagnosis. While there is yet no established pathognomonic histopathological feature to predict recurrence with all certainty, there is ongoing investigation for predictive markers of recurrence. Smoking seems to be a recognized risk factor for developing multiple recurrences and there is evidence that the presence of HPV serotypes 16 and 18 could be predictive of malignant transformation. The main aim of treatment is to achieve compete surgical resection and to prevent recurrence and malignant transformation. A period of clinical follow up is recommended after treatment. The aim of this review is to provide a comprehensive and updated overview of the clinical presentation, diagnosis, management and prognosis of this unique lesion.