Fungal Diseases of the Paranasal Sinuses

Fungal rhinosinusitis comprises a heterogeneous group of diseases affecting the nasal cavity and paranasal sinuses, ranging from non-invasive colonization to rapidly progressive, life-threatening invasive infections. The clinical course and prognosis largely depend on the host immune status and the presence of tissue invasion, with invasive forms posing a high risk of orbital and intracranial complications. In recent years, the incidence of fungal rhinosinusitis has increased, likely due to improved diagnostic modalities, wider use of endoscopy, and a growing population of immunocompromised patients, including those with diabetes mellitus and post-COVID-19 conditions. This article provides a comprehensive review of fungal rhinosinusitis, focusing on current classification, epidemiology, pathophysiology, clinical manifestations, diagnostic strategies, and management principles. According to histopathological criteria, fungal rhinosinusitis is classified into non-invasive forms (saprophytic colonization, fungal ball, and allergic fungal rhinosinusitis) and invasive forms (acute invasive, chronic invasive, and granulomatous invasive fungal rhinosinusitis). Non-invasive disease typically affects immunocompetent individuals and is characterized by localized fungal accumulation or hypersensitivity reactions without tissue invasion, whereas invasive forms predominantly occur in immunocompromised patients and are associated with angioinvasion, tissue necrosis, and bone destruction. Diagnosis relies on a combination of clinical evaluation, endoscopic findings, radiologic imaging, and definitive histopathological confirmation. Computed tomography plays a key role in identifying hyperdense fungal material and bony changes, while magnetic resonance imaging is essential for assessing soft-tissue involvement and extrasinus extension. Management strategies vary according to disease type and include surgical intervention, systemic antifungal therapy, and correction of underlying predisposing factors. A clinical case of isolated sphenoid fungal rhinosinusitis with optic nerve compression is presented, illustrating the diagnostic challenges and therapeutic considerations. Successful treatment was achieved with endoscopic transnasal sphenoidotomy, followed by close postoperative surveillance. This case highlights the importance of early recognition, accurate diagnosis, and individualized management to prevent irreversible complications and ensure favorable outcomes.