Light and electron microscopic study of primary atrophic rhinitis mucosa

This study examined the light and the electron microscopic changes in the mucosa of primary atrophic rhinitis and compared them with the normal nasal mucosa to establish the changes in the surfactant system. A prospective original study was performed.

Twenty cases of primary atrophic rhinitis were randomly selected in the outpatient clinic of Sohag University Ear, Nose, and Throat Department. Ten volunteers with no history of chronic nasal disease and with normal rhinopharyngeal picture were selected as control cases. A small punch biopsy was performed with a small forceps under local anesthesia from the medial edge of the inferior turbinate. After histological laboratory preparations, semithin sections (0.5-1 microm) were prepared by using an LKB ultramicrotome. The sections were stained by toluidine blue, examined by light microscope, and photographed. Ultrathin sections (500-800) from selected areas of the trimmed blocks were made and collected on copper grids. The ultrathin sections were then contrasted in uranyl acetate for 10 minutes and examined by electron microscope Jeol JEM-1010.

Light microscopy of primary atrophic epithelium revealed typical nonkeratinized stratified squamous epithelium to keratinized squamous epithelium with a thin layer of keratin on the surface. Well-developed desmosomes appeared between the epithelial cells. In the lamina propria, no submucosal glands could be seen. Electron microscopy of it revealed that the stratification of the epithelium increased. Sloughing of the superficial cells was observed in some regions of the proliferating epithelium. Epithelial penetration with neutrophils (mainly) and lymphocytes (some) could be seen. No numerous multilamellar bodies (MLBs) could be detected in these cases. An increased amount of collagenous fibers was observed in the basement membrane.

In primary atrophic rhinitis, the epithelial cells revealed that desmosomes are characteristic of the metaplastic squamous epithelium and had no MLB in their cytoplasm, and cells in which occasional MLBs had been established showed interdigitations between them and the surrounding cells, suggesting an association between the surfactant deficiency and the development of desmosomes.