Characteristics of Sinus Fungus Ball: A Unique Form of Rhinosinusitis

OBJECTIVE: The purpose of this study was to investigate the characteristics of this unique form of rhinosinusitis. METHODS: Ninety-one patients with sinus fungus balls were evaluated for clinical characteristics. Nasal tissues obtained from 38 patients with sinus fungus ball, along with 26 controls were used for histopathological, cytokines/chemokines, western blotting, and genetic analyses. RESULTS: Patients with fungus balls had significantly more females and their age was older. The presentation of fungus ball was predominantly unilateral (97.8%). Thirty-three patients (36.3%) had risk factors for fungal infection. Macrophage and neutrophil dominated cellular infiltration was found in nasal tissues of fungus ball patients. A tendency of reduced tight junction staining (e-cadherin) and protein expression was found. Interleukin 8 (IL8) and granulocyte colony stimulating factor (G-CSF) significantly increased in sinus fungus ball tissue homogenates when compared with those from controls. Higher prevalence of a single single nucleotide polymorphism (SNP) with E-cadherin was found in the patients with fungus ball. CONCLUSIONS: We found that patients with sinus fungus ball had robust immune responses, allowing recruitment and activation of macrophages and neutrophils. However, patients with sinus fungus ball could have genetic or acquired weakness in immunity. The fungal hyphae were localized and accumulated within single sinus instead of being eradicated by host.