RESUMEN
We present the first and only case, reported in literature, of a 67-years-old man with a mycotic aneurysm (MA) of the left posterior inferior cerebellar artery (PICA), caused by group B Streptococcus, that we surgically treated, performing neck aneurysm clipping, preserving patency of parent vessel. Moreover the peculiarity of this case is represented by the fact that the MA is originated from a tooth abscess, treated about two years before. To date, there have been only 10 cases of association between MA with either tooth pathologies or dental surgical procedures and our case is the only one originating from PICA. Therefore an extensive literature analysis was performed. Hence if we observe a patient with a fusiform aneurysm in posterior intracranial circulation and clinical history of fever and/or persistent neck swelling after dental pathologies, it is mandatory to consider the possibility of a MA, for a correct differential diagnosis. If the diagnosis is confirmed, it is necessary to research the origin of infection and to set the specific antibiotics therapy.