June 2018
A 42-month-old girl with a 1-year history of epilepsy and facial weakness presents with generalized tonic-clonic seizures, vomiting, and an altered level of consciousness.
Supratentorial Fungal Infection Mimicking Pilocytic Astrocytoma
- Background:
- Fungal infections in the CNS are rare in the general population; however, they are becoming increasingly more common.
- Immunocompromised patients are at a much higher risk for fungal infections.
- Fungal infections carry significant morbidity and mortality, and their diagnosis and treatment can still prove challenging.
- Early diagnosis and prompt initiation of appropriate management are vital to achieving good outcomes.
- Clinical Presentations:
- CNS fungal infections present as various clinical syndromes. More common presentations include syndromes of space-occupying lesions (such as cerebral abscesses, granulomas, etc.), basal meningitis, hydrocephalus, spinal infections, and stroke syndromes.
- Symptomatic CNS fungal infections are generally at greater risk of morbidity and mortality compared with viral, bacterial, and parasitic CNS disorders.
-
Key Diagnostic Features:
- The radiologic appearance of a fungal mass is variable.
- Some lesions (Aspergillus infections) have targetlike patterns, which are characterized by an intermediate-to-low peripheral T2 signal intensity with central hyperintensity.
- Mucormycosis commonly involves the frontal lobes and may appear hypointense or hyperintense on T2WI.
- Cryptococcomas can appear as gelatinous pseudocyst formations, with T2-hypointense rings surrounding a hyperintense center.
- Differential Diagnosis:
- Fungal CNS infections are frequently misdiagnosed as pyogenic abscesses, tuberculous meningitis, or neoplasms in the brain, as the radiographic appearance is, on its own, not specific.
-
Treatment:
- Main treatment option is antifungal therapy with polyenes, including Amphotericin B and azoles such as fluconazole.
- Over the last 2 decades, many useful antifungal drugs have been introduced. These include the lipid-based formulations of Amphotericin B, the newer triazoles, and most recently, echinocandins.
- The use of these medications in effective combinations has increased over the years, and literature supports their continued role in the management of invasive fungal infections.
