Skull base invasive aspergillosis in a peritoneal dialysis patient: A rare and devastating complication.

Aspergillus mastoiditis with skull base osteomyelitis is an exceptionally rare but life-threatening infection in patients undergoing peritoneal dialysis (PD). We report a 60-year-old man with diabetic kidney failure on PD who developed invasive Aspergillus flavus mastoiditis progressing to skull base osteomyelitis. Despite early mastoidectomy, PD catheter removal, and voriconazole therapy achieving therapeutic levels, the infection advanced to involve the carotid sheath and parapharyngeal space, resulting in severe neurologic and systemic complications. Molecular sequencing confirmed A. flavus, excluding cryptic species such as A. tamarii. This case represents the first documented instance of skull base invasive aspergillosis in a PD patient and underscores the importance of early suspicion, species-level molecular confirmation, and multidisciplinary management in this formidable and rapidly progressive condition.