Invasive Sphenoidal Aspergillosis With Orbital Involvement in an Immunocompetent Patient: A Case Report

Invasive aspergillosis of the sphenoid sinus is a rare condition, especially in immunocompetent patients, and may present as refractory headache and progress with neurological signs due to proximity to critical structures. We report the case of a 42-year-old woman, pharmacist, with a history of quadrantectomy for benign neoplasm in 2008, living in a rural area, who developed intense headache in October 2024, progressive and refractory to symptomatic medications, with no response to antibiotics prescribed for presumed bacterial sinusitis. After multiple evaluations, she progressed with diplopia and left sixth cranial nerve palsy. Brain MRI showed an expansive lesion in the left orbital apex extending to the sphenoid sinus. She underwent transcranial biopsy in January 2025, and histopathology revealed septate, branching hyphae with PAS and Grocott-positive staining. HIV and viral hepatitis serologies were negative, and initial chest CT was unremarkable. Negative initial cultures prompted the initiation of itraconazole and referral to the infectious diseases outpatient clinic. On evaluation, hospitalization for liposomal amphotericin B, restaging imaging, and planning of a new surgery was recommended. Serum antibodies against Aspergillus by immunocounterelectrophoresis and serum galactomannan were negative. Repeated chest and abdominal CT scans showed no abnormalities. The patient underwent a new surgery for abscess drainage; culture of the secretion grew A. fumigatus and S. viridans. Treatment included amphotericin B and ampicillin-sulbactam. She developed transient renal toxicity, hypomagnesemia, and hypokalemia, which were managed clinically. There was clinical and neurological improvement. She was discharged on oral voriconazole, provided by the Endemic Mycoses Program, and amoxicillin-clavulanate, with outpatient follow-up and progressive improvement. Despite its rarity, fungal paranasal abscesses should be considered in the differential diagnosis of persistent headache with cranial nerve deficits, even in immunocompetent patients. Etiologic confirmation by histopathology and microbiology is essential, and early surgical intervention combined with prolonged antifungal therapy is crucial for infection control and functional recovery.