Delayed implant infection with Cutibacterium acnes (Propionibacterium acnes) 30 years after silicone sheet orbital floor implant

Purpose: To report a case of delayed implant infection with Cutibacterium acnes (C. acnes, previously known as Propionibacterium acnes) 30 years after silicone sheet orbital floor implant. Methods: Case report with orbital imaging. Results: A 61-year-old male with a history of traumatic orbital floor fracture right eye (OD) repaired using a silicone sheet orbital floor implant 30 years prior, presented with 6 months of painless blepharoptosis and diplopia OD. On examination, there was 3 mm right upper eyelid blepharoptosis and hyperglobus. There was no globe proptosis, dysmotility, or compression and no cutaneous erythema, hyperthermia, discharge, or tenderness to palpation. Orbital magnetic resonance imaging (MRI) revealed a cystic mass in the inferior orbit in the region of the floor implant, measuring 25 mm in diameter and 10 mm in thickness. By MRI, T1-weighted images revealed a hypointense signal within the mass and T2-weighted images showed hyperintense signal with a flat hypointensity centrally representing the floor implant. Microbiologic cultures grew C. acnes. Conclusions: C. acnes can manifest several decades after placement of an orbital prosthetic implant, leading to delayed infection.