Purpose: To evaluate the potential of Histoplasma capsulatum to cause optic neuritis in the setting of the acquired immunodeficiency syndrome (AIDS).
Methods: We examined a 35-year-old man with a history of AIDS and disseminated histoplasmosis who developed a unilateral progressive optic neuritis of enigmatic origin. An optic nerve sheath biopsy was performed to provide a tissue diagnosis.
Results: Histoplasma capsulatum was identified in both the optic nerve sheath and fungal culture.
Conclusion: Histoplasma capsulatum should be considered in the differential diagnosis of optic neuritis in patients with AIDS, even in the absence of chorioretinal findings.