Non-epidermoid Epithelial Neoplasms

Abstract

Most cases of carcinoma of the nasal cavity and paranasal sinuses — a rare entity — are of epidermoid type so that the numbers of non-epidermoid carcinomas are very small indeed. Adenocarcinomas amount to only 6 · 2% of nasal carcinomas (Robin et al. 1979). These neoplasms are derived from (a) columnar cells of surface origin, (b) columnar cells of seromucinous glands or (c) myoepithelial cells associated with the latter. It would seem natural, therefore, to subdivide non-epidermoid epithelial neoplasms into those derived from surface epithelium and those from seromucinous glands (Table 17.1). The latter have a homology with salivary glands both in their normal appearance and in the types of their tumours. The sole benign neoplasm of surface respiratory epithelium, the cylindric cell papilloma, has been described in Chap. 15. In the case of the malignant form of respiratory epithelium — adenocarcinoma — it is usually not possible to determine whether the neoplasm is derived from the surface cylindric cells or from the deeper glandular cells, and this neoplasm will be considered as a single entity. Extremely well-differentiated glandular neoplasms have sometimes been called adenoma, but since an aggressive behaviour has on occasion been noted, they are best designated as low-grade adenocarcinomas (Heffner et al. 1982).