An autopsy case of invasive sino-orbital aspergillosis presenting the “tram-track” sign and “donut configuration” in the orbital magnetic resonance imaging

An 84-year-old man with diabetes mellitus presented with a right orbital apex syndrome. In the orbital magnetic resonance imaging, the fat-suppressed T2-weighted image showed a hyperintense parallel linear lesion on the right optic nerve and a ring lesion around it, producing the “tram-track” sign on the axial view and the “donut configuration” on the coronal view. A trans-sphenoid endoscopic orbital biopsy showed an infection of Aspergillus fumigatus. Despite treatment with oral voriconazole, the patient died from deterioration of chronic heart failure. An autopsy found normal tissue around the orbital portion of bilateral optic nerves, while Aspergillus was found around the optic chiasm. The “tram-track” sign and the “donut configuration” in the orbital magnetic resonance imaging were beneficial for the diagnosis of invasive sino-orbital aspergillosis.