Sinonasal Inverted Papilloma : Evaluating the Effectiveness of Prediction of the Site of Attachment based on Computed Tomography Scans

Sinonasal inverted papilloma is a benign neoplasm of epithelial origin, which represents 0.5 to 4% of all sinonasal tumors. Despite the histological benign nature of this type of tumor, it has a high rate of recurrence after surgical resection and significant malignant potential. Sinonasal inverted papilloma is treated as a locally aggressive tumor. The aggressive surgical approaches, such as en bloc resection via external excision or extensive mucosal stripping of the ipsilateral sinuses are replaced by less invasive intranasal endoscopic approaches. This creates a need for a very accurate preoperative assessment of the location of the tumor on computed tomography (CT) scan and identifies the location of the primary changes. Determination of the primary location of inverted papilloma is especially important for a radical resection of the tumor, because the tumor recurs mostly in the same location as the primary lesion. The aim of this study was to determine the relationship between changes in the preoperative CT scan of the paranasal sinuses and the location of papilloma by histological examination of surgical material. In this study, we evaluated the changes in the preoperative CT scans in the form of focal hyperostosis and erosion of the walls of the paranasal sinuses. Examined groups consisted of 12 people diagnosed with inverted papilloma and 15 peoples diagnosed with preinverted papilloma. Focal hyperostosis occurred in 83% of cases of inverted papilloma. Their location corresponded to 90% of the primal attachment of the tumor. Among the preinverted papillomas, focal hyperostosis occurred in less than 7% of the cases and did not correspond to the location of papilloma inverted. The analysis of remodeling and erosion of bone walls of the sinuses showed their presence in 67% of cases of inverted papilloma and 40% of cases of preinverted papilloma. However, their overlap with the location of the tumor was 50% for the inverted papilloma and 33% for the preinverted papilloma. Erosion and sinus bone destruction do not coincide closely with the primary location of the papilloma, because it is more the result of bone compression by the growing mass than bone invasion. The sites of focal hyperostosis closely coincide with the place of origin of the inverted papilloma, but the pathophysiological mechanism of this phenomenon is not fully understood. The relationship between the sites of focal hyperostosis and the location of the primary tumor can be used when planning surgery for accurate resection.