Detection of an unusual inverted schneiderian papilloma by cone beam computed tomography.

An inverted schneiderian papilloma (ISP) is a rare neoplasm that affects the nasal cavity or a paranasal sinus, especially the maxillary sinus. Although histologically benign, the lesion has a high potential for local destruction, has a high recurrence rate, and presents the possibility of malignant transformation into squamous cell carcinoma. To determine the extent of the injury and possible impairment of adjacent maxillofacial structures, accurate imaging, such as cone beam computed tomography (CBCT), is necessary. A 47-year-old man reported a nasal obstruction on the right side of his face, signs of oroantral communication, and facial asymmetry. The CBCT examination revealed an extensive lesion of mixed density and irregular contours involving the entire right maxillary sinus and nasal cavity. The association between the clinical signs and symptoms and the tomographic features of the lesion resulted in a differential diagnosis of an ISP, which was confirmed through histopathologic examination. This case report confirms that CBCT is a valuable method for the detection of pathologic alterations affecting the maxillary sinus, especially ISPs.