Chronic allergic fungal sinusitis invading the skull base in an immunocompetent male: illustrative case.

BACKGROUND: Allergic fungal sinusitis (AFS) is an immunoglobulin E-mediated reaction to fungal organisms in the sinonasal region and can be categorized as acute or chronic. Acute infection is typical in immunocompromised patients, while chronic infection is classically seen in immunocompetent patients. Spread of infection to the skull base is a rare and potentially lethal complication of prolonged infection. Surgical management is frequently augmented with steroid therapy to prevent recurrence. OBSERVATIONS: The authors present a case of a 20-year-old African American male with prolonged headaches and blurred vision who was diagnosed with chronic invasive fungal sinusitis resulting in invasion of fungal burden into the anterior skull base and the posterior aspect of the clivus, in addition to complete obliteration of the maxillary sinus. The patient was managed surgically without complication and with gradual improvement in vision. LESSONS: Early management and detection of AFS should be a focus to prevent erosion of the fungal burden into the skull base. Neurosurgery and ear, nose, and throat surgery have a multidisciplinary role in the management of advanced AFS cases.