408. Invasive Fungal Petrositis and Carotiditis (IFPAC) Syndrome in Immunocompromised Hosts: An Unrecognized, Often Catastrophic Invasive Fungal Disease (IFD)

BACKGROUND: Infections involving the petro-clival junction of the temporal bone are rare and primarily caused by Pseudomonas aeruginosa in the setting of progressive malignant otitis externa (skull base osteomyelitis). IFD, including invasive aspergillosis (IA), are not often considered in the evaluation of these patients. METHODS: We conducted a retrospective study of patients diagnosed with fungal skull base petrositis at our institution from 2003 to 2018. We collected data including demographics, clinical presentation, imaging, diagnostic evaluation, treatment, microbiology, and outcomes. RESULTS: We identified four cases of IFPAC. Median age at presentation was 73 years (range, 66–79), 3 were male. IFD risk factors included diabetes (n = 3), glucocorticoid use (n = 3), and lymphoid malignancy (n = 2). Two patients were on additional T-cell immunosuppressants. Patients presented with otalgia (n = 2) or headaches (n = 2). Two patients developed cranial nerve deficits (III, V, VI), two had hearing loss and trigeminal neuralgia. All cases were caused by Aspergillus spp. (3 proven, one probable IA). Two cases were otogenic, two were sinusal in origin. Proven cases were confirmed by biopsy of mastoid cortex or sinus tissue. Median time from symptom onset to diagnosis was 17 weeks (range, 6–36). All patients were treated with anti-Aspergillus antifungals with initial improvement in symptoms, imaging, or decrease in galactomannan levels. All patients eventually presented with occlusion of the internal carotid artery (ICA) and multiple cerebral infarcts. Two patients were diagnosed with mycotic aneurysms involving (a) ICA with rupture necessitating endovascular intervention and vessel sacrifice; (b) basilar summit with subarachnoid hemorrhage. Three patients died following these vascular events, while one patient underwent left ICA bypass with improvement in symptoms. CONCLUSION: IFPAC is a rare, but distinct manifestation of IFD and was caused by IA in this series. All patients experienced carotid vascular events and two patients had associated mycotic aneurysms despite symptomatic and radiologic improvement on antifungal therapy, raising the question if more aggressive surgical or endovascular interventions need to be considered in this syndrome. DISCLOSURES: F. M. Marty, Merck: Consultant and Investigator, Consulting fee, Research support and Speaker honorarium. Astellas: Consultant and Investigator, Consulting fee and Research support. Chimerix: Consultant and Investigator, Consulting fee and Research support. Fate Therapeutics: Consultant, Consulting fee; GlaxoSmithKline: Consultant, Consulting fee. LFB: Consultant, Consulting fee. Roche Molecular Diagnostics: Consultant, Consulting fee. Shire: Consultant and Investigator, Consulting fee and Research support.