Cluster headache-like pain in multiple sclerosis

We describe a case with simultaneous occurrence of cluster headache-like pa in and multiple sclerosis. Both neuroimaging and neurophysiology (trigemina l evoked potentials) revealed a demyelination plaque in the pens, at the tr igeminal root entry zone, on the side of pain. Although that type of lesion is usually associated with trigeminal neuralgia pain, we hypothesize that in this case it may be linked with the concomitant cluster headache, possib ly by activation of trigemino-vascular mechanisms.