Rare Listeria monocytogenes brain abscess presenting as a tunnel-like lesion in an immunocompromised patient.

Cerebral abscesses caused by Listeria monocytogenes are very rare and mainly occur in immunocompromised and elderly patients. Brain abscesses caused by Listeria monocytogenes are characterized by a typical tunnel-like appearance, which may be considered a pathognomonic MRI feature and is thought to be the result of intra-axonal spread of the pathogen.