Persistent extra-axial post-surgical collections and Propionibacterium acnes infection. Presentation of two cases and literature review.

Objectives: It is common to observe the persistence of extra-axial collections after craniotomies. Most of these disappear in weeks or months but some remain. The onset of focal symptoms or the growth of these persistent collections months or years after surgery may indicate the presence of a chronic and latent infection by germs of low virulence such as Propionibacterium acnes (P.