Central nervous system histoplasmosis mimicking a brain tumor: difficulties in diagnosis and treatment.

Neurologic involvement occurs in 10% to 20% of patients with disseminated histoplasmosis. We describe a 20-year-old woman who had headache and diplopia but no evidence of systemic infection. Magnetic resonance imaging showed an enhancing mass in the thalamomesencephalic and third ventricular region. After subtotal resection of what was presumed to be a glioma, the patient had symptoms and signs of meningitis. Subsequent pathological review demonstrated noncaseating granulomas, and serologic tests and cultures confirmed the diagnosis of histoplasmosis. Initiation of antifungal therapy and removal of an infected shunt system resulted in clinical improvement. Clinicians should maintain a high index of suspicion in patients who are from any area endemic for histoplasmosis.