Listeria monocytogenes is associated with rhombencephalitis. However, the exact 
mechanisms of brainstem invasion remains poorly understood. Here, we demonstrate 
clinical and radiological data suggesting that Listeria may invade the brainstem 
via the trigeminal nerve. Three females (41, 64 and 70 years) with culture 
proven L. monocytogenes bacteremia and rhombencephalitis were investigated in 
the period of 2014-16. T2-weighted and contrast-enhanced T1-weighted MRI 
revealed a cerebellopontine abscess in all three patients, including the 
involvement of the trigeminal nerve root. In two patients, MRI also revealed 
selective contrast enhancement of the sensory trigeminal tract in the pons and 
medulla oblongata. Prior to any other neurological symptoms, two patients 
complained of hypoesthesia and a tingling sensation in the ipsilateral half of 
the face, consistent with sensory trigeminal nerve dysfunction on that side. In 
addition, we identified another 120 cases of Listeria rhombencephalitis 
following a systematic review. Cranial nerves VII, V, IX, and X, respectively, 
medulla oblongata, cerebellum and pons, were the most frequently involved brain 
structures. The present clinical and radiological findings corroborate earlier 
data from animal experiments, indicating that L. monocytogenes may be capable of 
retrograde intra-axonal migration along the cranial nerves. We suggest that in a 
subset of patients with rhombencephalitis L. monocytogenes enters the 
cerebellopontine angle through the trigeminal nerve, invading the brainstem via 
the sensory trigeminal nuclei.