BACKGROUND: An inverted papilloma (IP) is a benign sinonasal tumor of ectodermal origin, which is locally aggressive and destructive, tends to recur if incompletely removed, and has significant malignant potential. On CT scan, the appearance of an IP is variable and nonspecific but most commonly it appears to have soft tissue density. The association of IPs and new bone formation is extremely rare; to the best of our knowledge, only one case has been reported in the literature to date. METHODS: We report three cases with existence of bony mass surrounded by polypoid soft tissue diagnosed as IP histopathologically. RESULTS: The nature, shape, and location of the bony mass were not in concordance with trapped bone, with tumoral calcifications, or with osteoma. CONCLUSION: We propose that with regard to the three cases presented here, new bone formation may be associated with IP pathologically. We also believe that additional investigations are required to characterize the pathophysiological mechanisms involved in neoplasm-induced osteogenesis.
BACKGROUND: An inverted papilloma (IP) is a benign sinonasal tumor of ectodermal origin, which is locally aggressive and destructive, tends to recur if incompletely removed, and has significant malignant potential. On CT scan, the appearance of an IP is variable and nonspecific but most commonly it appears to have soft tissue density. The association of IPs and new bone formation is extremely rare; to the best of our knowledge, only one case has been reported in the literature to date. METHODS: We report three cases with existence of bony mass surrounded by polypoid soft tissue diagnosed as IP histopathologically. RESULTS: The nature, shape, and location of the bony mass were not in concordance with trapped bone, with tumoral calcifications, or with osteoma. CONCLUSION: We propose that with regard to the three cases presented here, new bone formation may be associated with IP pathologically. We also believe that additional investigations are required to characterize the pathophysiological mechanisms involved in neoplasm-induced osteogenesis.