Trigeminal Pontine Sign: From Imaging to Diseases Beyond Trigeminal Neuralgia.

The so-called trigeminal pontine sign has been described as a marker of different diseases, from multiple sclerosis to herpetic infections. First, it has been proposed as linear hyperintensity in the pons on the Magnetic Resonance Imaging (MRI) of patients with multiple sclerosis and trigeminal neuralgia. After these descriptions, it has been reported as incidental findings in the same patients and in patients with HSV or VZV infections. In addition, patients with neuromyelitis optica spectrum disorders (NMOSD) have been more rarely described with this neuroradiological sign. In this review, the main anatomical and neuroradiological issues underlying the trigeminal pontine sign are described, together with the limitations of the published studies from the clinical and neuroimaging point of view. Finally, the association with different diseases is detailed.