IntroductionCutibacterium acnes is a Gram positive, anaerobic bacterium of low pathogenic potential that forms part of the normal cutaneous flora. Although most often identified as a contaminant in culture of microbiological specimens, it is commonly implicated in both postoperative wound and implantable device infection. Neurosurgical device infections secondary to C. acnes are well recognised and are likely secondary to bacterial contamination from the skin during surgery. Indolent infection characterised by delayed presentation of weeks to months following intervention is common. C. acnes infection involving the central nervous system (CNS) in the absence of previous neurosurgical intervention is rare, but has been described following dental or mastoid infections and following facial trauma. A further case series has reported de novo C. acnes CNS infection occurring in the absence of these recognised risk factors, but with clinical features of meningitis being common to all.Methods and resultsWe describe a unique case of primary C. acnes extra-dural collection in a previously well patient with no neurosurgical history presenting with sub-acute focal seizures and progressive focal leptomeningeal thickening on MRI.ConclusionC. acnes CNS infection can occur in the immunocompetent and in the absence of neurosurgical intervention.