Sinonasal inverted papilloma is an uncommon benign tumor that arises from the schneiderian membrane, which consists of ciliated columnar epithelium of ectodermal origin in the sinonasal mucosa. An incidence of 0.2 to 0.7 cases per 100 000 population per year has been reported, representing 0.5% to 4% of all nasal tumors.1 Typically, SIPs are more prevalent among males and occur more frequently in the fifth and sixth decades of life. Approximately 80% of SIPs originate from the lateral wall of the nasal cavity, near the middle turbinate.1 There are 3 characteristic attributes of a SIP: (1) its tendency to recur; (2) its destructive or bone remodeling capacity; and (3) its propensity to be associated with malignant neoplasms, especially squamous cell carcinoma (SCC). According to a review of the literature, there may be a viral component in the pathogenesis of SIPs, as demonstrated by the detection of human papillomavirus DNA within SIPs by in situ hybridization.2 However, the virus inclusions have never been equivocally demonstrated by either light or electron microscopy.3 Human papillomavirus as an etiologic agent of SIP is still controversial. Other factors, such as bacterial infections, inflammation, allergies, tobacco, and occupational exposures, have been cited as possible causes, but the exact mechanisms of growth and malignant transformation of SIPs are still unknown.1
Pathology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2012;138(6):602–603. doi:10.1001/archoto.2012.497b
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