Acute sinusitis: A histopathological and immunohistochemical study

Objective: To provide data on the histopathological and immunohistochemical characteristics of acute sinusitis in humans. Study Design: A nonrandomized, retrospective, controlled, qualitative and quantitative study. Methods: Inflamed sinus mucosal tissues were removed during functional endoscopic sinus surgery from 11 patients with acute sinusitis, of whom 6 had complications with extension of inflammation to the orbit (4) or the meninges (2), 3 had recurrent sinusitis, and 2 had acute exacerbation of chronic sinusitis. Normal sinus mucosal tissues were retrieved from four patients with various nasal tumors and served as controls. All specimens underwent routine histological processing. Representative sections from each region were stained with hematoxylin and eosin, periodic acid-Schiff, and toluidine blue. Immunohistochemical staining for T and B lymphocytes was also applied. A two-phase examination was designed: low-magnification microscopic assessment (x 40) to yield the typical pathological features and high-magnification assessment (x 400) to count various inflammatory cells, Results: The lamina propria displayed the most significant changes with edema, extensive infiltration of neutrophils and mononuclear cells, formation of microabscesses, thrombophlebitis, and necrotic foci, whereas the involvement of the epithelial layer in the inflammatory reaction was relatively modest. Immunohistochemistry revealed an increase in the population of T and B lymphocytes. The former were diffusely scattered, whereas the latter also formed distinct clusters: around small venules, adjacent to seromucous glands, and under the epithelium. Conclusions: The inflammatory reaction of the lamina propria exceeded that of the epithelial layer. It is assumed that the clusters of B lymphocytes around blood vessels may point to the fact that these cells were recruited from the blood during acute sinusitis.