Invasive Aspergillosis with Intracranial Extension Initially Misdiagnosed as a Granulomatous Disease: A Case Report

Background: Invasive aspergillosis with orbital apex and intracranial involvement is rare and often misdiagnosed due to nonspecific imaging findings. Misinterpretation may lead to inappropriate therapies, such as corticosteroids, which can exacerbate fungal infections. Case Presentation: A 50-year-old immunocompetent woman with diabetes mellitus presented with right ptosis and systemic malaise. Magnetic resonance imaging (MRI) performed three months prior had shown a subtle low-signal lesion in the right orbital apex. The lesion was small and thought to represent a granulomatous process, with minimal systemic inflammation and only mild surrounding changes on imaging. Biopsy was considered too invasive at that stage, and the patient was placed under observation. Over time, her condition progressed, and repeat imaging revealed intracranial extension, including involvement of the cavernous sinus and frontal lobe. Differential diagnoses included granulomatous diseases such as sarcoidosis or tuberculosis, prompting empirical anti-tuberculosis treatment. However, the patient’s condition worsened, and biopsy of the sphenoid sinus revealed septated fungal hyphae consistent with Aspergillus species on Grocott staining. Voriconazole therapy was initiated, resulting in significant clinical and radiological improvement. Discussion: This case highlights the diagnostic challenge of identifying orbital apex aspergillosis with early MRI changes and demonstrates the risk of misdiagnosis as granulomatous disease. Differentiating fungal infections from other inflammatory etiologies based on subtle imaging features is critical, especially when considering immunosuppressive therapy. Conclusion: Clinicians should maintain a high index of suspicion for fungal infections in patients with progressive orbital apex lesions, even in the absence of classic immunosuppression. Early imaging review and biopsy are essential to prevent misdiagnosis and inappropriate treatment.