An Orbital Abscess Caused by Fusobacterium nucleatum Mimicking Tolosa-Hunt Syndrome.

Fusobacterium species, particularly Fusobacterium nucleatum, are anaerobic gram-negative bacteria found in the oral cavity and gastrointestinal tract. Infections caused by these organisms exhibit diverse clinical manifestations. Here we report a rare case of orbital abscess caused by Fusobacterium nucleatum, which was initially misdiagnosed as Tolosa-Hunt syndrome. The patient was controlled conservatively, and surgical intervention was withheld due to poor prognosis, diabetes, and logistical limitations. This case report highlights the need to consider infection even when imaging and laboratory tests are unremarkable, and to emphasize the importance of close follow-up of orbital abscesses due to its aggressive nature.