Spectrum of fungal rhinosinusitis; histopathologist's perspective.

Aims: Clinical presentation can provide a clue to the subcategories of fungal rhinosinusitis (FRS); however, tissue examination provides accurate classification. The aim was to analyse the incidence and histopathological spectrum of FRS.
Methods and Results: A retrospective analysis of all the cases of rhinosinusitis reported in the last 5 years was carried out. Haematoxylin and eosin-stained sections along with special stains such as periodic acid-Schiff and Grocott's were examined. These cases were subclassified based on the presence of allergic mucin, mycelial elements and tissue reaction. Out of a total of 665 cases of rhinosinusitis, 284 (42.7%) were of FRS. On histopathological examination they were broadly categorized as: (i) non-invasive FRS (n = 171, 60.2%), which included 160 cases (56.3%) of allergic fungal rhinosinusitis (AFRS) and eleven (3.9%) of fungal ball; (ii) invasive FRS (n = 101, 35.6%), which included 48 cases (16.9%) of chronic invasive granulomatous FRS, four (1.4%) of chronic invasive FRS and 49 (17.3%) of acute fulminant FRS; and (iii) mixed pattern FRS, comprising 12 cases (4.25%).
Conclusions: AFRS is the most common type of FRS. Cases with mixed reaction pattern suggest that different types of FRS represent a progressive spectrum of disease. An exact histopathological categorization of FRS is important as regards treatment.