Concomitant Histopathological Findings of Allergic Fungal Sinusitis and Fungal Ball in the Same Sinus: A Rare Case Report

Abstract

BACKGROUND: Allergic fungal sinusitis (AFS) and fungal ball (mycetoma) are two forms of noninvasive fungal sinusitis distinct in their clinical presentations, histopathologic features, treatment modalities, and prognoses. We report an unusual case where histopathological findings of both entities were found in the same sinus. CASE: A 63-year-old immunocompetent man with a history of allergic rhinitis, asthma and chronic rhinosinusitis (CRS) was referred to our clinic for worsening of asthma and sinonasal symptoms one year after undergoing maxillary sinus surgery. Laboratory investigations revealed peripheral eosinophilia (1300/μL) and a markedly elevated total IgE level (5469 kU/L; normal value <165 kU/L). Skin prick test was positive to A. fumigatus. The possibility of allergic bronchopulmonary aspergillosis was excluded with a normal CT of the chest. Sinus CT showed extensive mucosal changes of CRS; additionally, there was opacification associated with areas of calcification in the right maxillary sinus. At endoscopic sinus surgery, a large fungal ball embedded in thick mucus was recovered from the sinus. GMS staining showed dense branching fungal hyphae within the fungal mass and rare hyphal elements within the mucus. H&E staining revealed abundant clusters of eosinophils, consistent with allergic mucin. Mucosal biopsy demonstrated eosinophilic inflammation without fungal invasion. Cultures were negative. Systemic and topical steroids were initiated to reduce the eosinophilic inflammatory response and prevent disease recurrence. CONCLUSIONS: This is an unusual case of AFS and fungal ball coexistence in the same sinus, illustrating the importance of considering AFS as a diagnostic possibility in the presence of chronic rhinosinusitis associated with IgE-mediated hypersensitivity to fungi.