CT features of early Listeria monocytogenes cerebritis

Listeria monocytogenes is a relatively uncommon pathogen affecting infants or adults with predisposing conditions, such as cirrhosis, diabetes mellitus, autoimmune disease, renal transplants, and solid and lymphoreticular malignancies. Cerebral parenchymal involvement is rare and consists of focal cerebritis, which may progress to abscess formation. This article presents three cases of early Listeria monocytogenes cerebritis, two of which demonstrated ill-defined superficial areas of low attenuation with curvilinear gyral enhancement and one of which demonstrated a deep, low-attenuation lesion with faint surrounding enhancement. Although these findings are nonspecific, their early recognition in the proper clinical setting may help institute early antibiotic therapy, which appears to be successful without surgical intervention.