Clinical and histological aspects of malignant inverted sinonasal papilloma. Two case reports.

The inverted sino-nasal papilloma is a benign epithelial lesion, ranging from 1% to 5% of the tumors that reside in this area. It is characterized by a tendency towards local bone destruction, recurrence and malignant transformation. This is a presentation of two cases diagnosed and surgically treated for malignant inverted papiloma, which started in the epithelium of the maxillary sinuses. The cases had in common the late presentation of the patient to the surgeon, thus the local destruction was significant with extension towards the eye socket and the base of the skull. The treatment of choice was the surgical resection of the maxillary bone with a prosthetic reconstruction of the defect followed by radiotherapy. After a careful analysis of the two cases, a series of statements regarding the diagnosis and treatment of this rare pathology were recommended.