The ultrastructure of mast cells found in normal inferior turbinate was compared with the features found in the inferior turbinate in two groups of patients, those with allergic rhinitis due to dust mite hypersensitivity and those with nasal polyps; the latter group also had their polyps studied. Adenoid tissue was examined in children with secretory otitis media to see if there was evidence of mast cell degranulation, which would support the hypothesis that either local allergic or other mast cell-mediated reactions caused the condition.

The mast cells from five normal turbinates varied considerably in size, shape and distribution, but were found mainly in the submucosa. There was no difference in the morphology of cells of different sizes and they could not be sub-grouped into either connective tissue or mucosal mast cells. Most. granules were electron dense and homogeneous, although scrolls and crystalline structures were seen occasionally. Some of the granules contained lighter material and others had become vacuoles. Mitochondria were present in all cells suggesting active metabolism.

The three patients with allergic rhinitis showed extensive but variable degranulation of the mast cells in all depths of the mucosa. Nine of the 10 cases with nasal polyps had mast cells identified in both the polyp and the turbinate. They were only normal in one turbinate and in one patient it was impossible to identify mast cells. All the mast cells were degranulated extensively in all other specimens.

The adenoids from seven children had identifiable mast cells, which were less frequently found than in the turbinates. There was some degranulation in four of the patients and in one it was fairly extensive.