Classification of fungal rhinosinusitis (FRS) based on histomorphology and clinical presentation aids in early diagnosis and prompt patient management. In this retrospective observational study, clinicopathologic findings in patients diagnosed with fungal rhinosinusitis between January 2019 and December 2021 were evaluated. Clinical and imaging findings were retrieved from hospital records
slides from routine and histochemical studies were reviewed, and the cases were classified into non-invasive [fungal ball (FB) and allergic fungal rhinosinusitis (AFRS)] and invasive FRS [acute invasive fungal rhinosinusitis (AIFRS), chronic invasive fungal rhinosinusitis (CIFRS) and chronic invasive granulomatous fungal rhinosinusitis (CGFRS)]. Fungal cultures were also compared with histopathology. Of the 85 patients in the study, 34% were non-invasive (86% FB,10% AFRS, and 4% unclassified), and 66% were invasive (70% AIFRS, 21% CGFRS, and 9% CIFRS). The mean age of patients was 51 years, with a male-to-female ratio of 1.5:1. The most common comorbidity was diabetes with COVID-19 co-infection. Culture reports were available for 77 patients, of which 36 cases had growth, the majority of which were Aspergillus
7 patients had coinfection with Aspergillus and Mucorales. Comparing histopathology to the gold standard mycology for Aspergillus, a sensitivity of 90%, specificity of 96%, and Cohen's Kappa of 0.8 was achieved. This study emphasizes the value of an integrated diagnostic approach in arriving at an appropriate diagnosis. In resource-limited settings, histopathological evaluation can be a valuable screening tool, aiding in early diagnosis.