Mast cell quantitation in non- neoplastic polypoidal nasal lesions.

The distribution and abundance of mast cells was studied in 110 nasal non- neoplastic polypoidal lesions. In most of the polyps of all kinds, the epithelium showed less than 5000 mast cells/mm(1). Out of the 72 so- called "nonallergic polyps", 29 (40,3%) showed more than 20,000 mast cells/mm(1) in the subepithelial layer, and 30 (41.7%) more than 20,000 mast cells/mm(1) in the deeper areas. Out of the 18 so- called "allergic polyps", 8 (44.5%) showed more than 20,000 mast cells/ mm(3) in the subepithelial layer, and, 8 (44.5%) more than 20,000 mast cells/mm(3) in the deeper areas. Interestingly, mast cells were also seen in very high numbers in 33-38% of cases of chronic hypertrophic rhinitis, rhinosporidiosis and mucormycosis. There was no correlation between the proportion of eosinophils and mast cells in the lesions. We conclude that mast cells are not restricted to allergic nasal lesions and the significance of their presence in nasal lesions needs to be evaluated.