The inverted Schneiderian papilloma: a clinical and pathological study.

Inverted papillomas which arise from the lining membranes of the nose and paranasal sinuses are relatively unfamiliar lesions which have been reported in the literature under a variety of titles. The uncertainly surrounding their etiology, their relationship to nasal polyps and their malignant potential have resulted in an ill-defined clinical approach to their management. The designation Inverted Schneiderian Papilloma is suggested as an appropriate title that best conveys the qualities of inversion, location and distinctiveness of character. The characteristic microscopic feature is the increase in thickness of the covering epithelium with extensive invasion of this hyperplastic epithelium into the underlying stroma. In the absence of a better explanation of the origin, the tumor should be considered a true epithelial neoplasm. The clinical features in 24 previously unreported cases are presented. The most common presenting complaints are nasal obstruction and epistaxis. The common site of origin is the lateral nasal wall in the region of the middle meatus and ethmoid cells. In no instance was an isolated lesion of the maxillary, frontal or sphenoid sinus present. The most characteristic attributes of the tumor were its tendency to recur, its destructive capacity and its propensity to be associated with malignancy. The common radiographic abnormality on routine sinus films was unilateral opacification of the sinuses and nasal airway. Tomography is helpful in defining the extent of the lesion and in selecting an appropriate surgical approach. A philosophy of management has evolved based on the experiences gained from these 24 patients, combined with a review of the experience of others and a study of the regional anatomy. Surgical excision is the treatment of choice. A bold surgical approach has been used for tumors involving the lateral nasal wall and paranasal sinuses. A lateral rhinotomy incision is employed and when necessary, this exposure is increased by extending the incision of split the upper lip and reflect the cheek flap as is customarily done with the Weber-Ferfusson incision. Fifteen patients have been followed for more than two years and the results have been excellent with the exception of one patient who later developed an invasive squamous carcinoma. An associated malignancy was found in 12.5 percent of the cases.