BENIGN MUCOSAL TUMORS OF THE NOSE AND PARANASAL SINUSES

The histogenesis of benign mucosal tumors of the nose and paranasal si nuses is reviewed in this report. In contradistinction to the view fav ored in the literature, these comprise three distinct entities. Everte d and cylindric cell papillomas are true papillomas, lined by stratifi ed squamous and microcyst-laden, columnar, and oncocytic epithelium, r espectively, Inverted papillomas are polyps with marked, patchy squamo us metaplasia in ductal and surface epithelium and numerous microcysts containing macrophages in those epithelia, Low-grade squamous carcino ma of the nose and paranasal sinuses may be difficult to distinguish f rom inverted papilloma, There are no intermediate forms from any one o f the three types of benign mucosal tumors of the nose and paranasal s inuses to another. The site of origin of everted papilloma is from the nasal septum or nasal vestibular epithelium. Inverted and cylindric c ell papillomas arise on the other hand from the lateral wall of the no se, ethmoid, or maxillary sinuses. Inverted papillomas alone among the three have a strong tendency to recur, and some cases are associated with carcinoma, although the development of malignancy is unusual. Cop yright (C) 1996 by W.B. Saunders Company.