Orbital-centric invasive aspergillosis with infraorbital nerve enlargement in an immunocompetent patient: a case report.

Orbital aspergillosis is a rare but potentially life- and sight-threatening fungal infection that can affect both immunocompromised and healthy individuals. We present a case of orbital aspergillosis with infraorbital nerve enlargement in a healthy 30-year-old male who presented with progressive proptosis, diplopia, and vision decline. Nasal endoscopy was unremarkable. CT imaging revealed an ill-defined, infiltrative, hyperdense mass in the left inferior orbital region with presumed enlargement of the infraorbital nerve (ION) and expansion of the ION canal, along with pterygopalatine fossa involvement, while the sinuses were almost clear. MRI showed similar findings. Histopathological analysis confirmed Aspergillus fumigatus. Treatment with voriconazole led to significant clinical improvement. This case underscores the diagnostic challenges of orbital aspergillosis and highlights that ION enlargement should be cautiously interpreted as a specific sign of IgG4-related disease. It is crucial to maintain a high index of suspicion in cases of progressive proptosis, even in the absence of clear sinonasal involvement.