2021 Volume 64 Issue 3 Pages 150-156
Sinonasal inverted papilloma is the most commonly occurring benign tumor of the paranasal sinuses and is generally recognized as being unilateral. It has the potential for malignant transformation and is known to be associated with a high relapse rate. Herein, we report two cases of bilateral sinonasal inverted papilloma which were diagnosed at surgery. Preoperative biopsy suggested that the nasal tumor was an inflammatory nasal polyp, but frozen section examination revealed the diagnosis of bilateral inverted papilloma. Even in cases where a diagnosis of unilateral sinonasal inverted papilloma has been made, it must be assumed that there could be a neoplastic lesion on the opposite side. Therefore, detailed intranasal observation is important. In some cases, preoperative histological diagnosis and intra-operative diagnosis are essential.
