Lipoid meningitis due to aseptic necrosis of a free fat graft placed during neurotologic surgery

We present two unusual cases of aseptic postoperative lipoid meningitis resulting from necrosis of a free fat graft placed into a skull base craniotomy defect. Two patients underwent translabyrinthine resection of acoustic neuroma and received abdominal fat grafts to ablate the surgical defect. Both patients presented postoperatively with persistent cerebrospinal fluid (CSF) wound leak and severe headache. Computed tomography demonstrated hydrocephalus and widely dispersed intracranial fat droplets throughout the CSF circulation. Both patients ultimately required CSF diversion for management of persistent communicating hydrocephalus. The clinical and radiographic correlates of lipocephalus and lipoid meningitis are presented, and a review of free fat graft physiology is discussed.