A Case of Central Nervous System Aspergillosis Associated with Fungal Sphenoid Sinusitis Presenting with Bilateral Hemianopia and Diagnosed by Optic Pathway System Biopsy

Presenting with bilateral hemianopia and diagnosed by optic pathway system biopsy invasive fungal sinusitis can affect cranial nerves, including the optic nerve. Differential diagnosis is challenging in cases in which the typical imaging findings of fungal sinusitis are absent. Aspergillus spp. are the most common cause of invasive fungal sinusitis. Spread to the central nervous system (CNS) can lead to CNS aspergillosis, which is associated with a significant mortality risk, especially in immunocompromised hosts when the initial treatment is delayed. Identifying the species and conducting susceptibility testing are crucial for choosing the appropriate antifungal drugs for treatment. However, owing to the low sensitivity of Aspergillus spp., appropriate selection of the specimen collection method is crucial to obtain reliable results. In this report, we describe a case of CNS aspergillosis in a 77-year-old male patient who presented with bitemporal hemianopsia as the initial symptom while receiving chemotherapy and steroid therapy for multiple myeloma. Despite absence of the typical imaging findings of invasive fungal sinusitis, a biopsy of the optic pathway system confirmed the diagnosis of Aspergillus sphenoid sinusitis with intracranial extension. In cases of CNS aspergillosis secondary to invasive sinus fungal infection, neurological manifestations can precede radiological evidence. Patients at risk of CNS aspergillosis require prompt sinus biopsy when neurological manifestations suggest the possibility of invasive fungal sinusitis. A biopsy near the optic chiasm in addition to the nasal sinuses may provide valuable information in patients presenting with bilateral hemianopsia.