A Collet–Sicard syndrome due to internal carotid artery dissection associated with cerebral amyloid angiopathy–related inflammation

BACKGROUND: Cerebral amyloid angiopathy–related inflammation is a rare condition with approximately 100 reported cases. Its clinical manifestations are varied. We report here a novel presentation of this disease. CASE PRESENTATION: A 61-year-old Caucasian man presented with rapidly progressive paralysis of the IX, X, XI and XII right cranial nerves associated with right central facial nerve palsy. Brain computed tomography angiography and cerebral catheter angiography found a focal fusiform enlargement of the distal cervical portion of the right internal carotid artery, related to a pseudo-aneurysm suggesting an evolution of a dissection and intra-cranial vessel dysplasia. Brain magnetic resonance imaging showed multiple asymmetrical subcortical regions of hyperintensity on T2 fluid-attenuated inversion recovery sequences. Punctiform cortical hyposignals on T2-weighted gradient echo magnetic resonance imaging sequences were mostly congruent with the white matter hyperintensities. There was a decreased cerebral perfusion at the frontal hyperintense fluid-attenuated inversion recovery region. Spectrometry identified a lactate–lipid peak. A brain biopsy showed intravascular amyloid deposits. Corticosteroid therapy was initiated, leading to a dramatic improvement of both clinical condition and magnetic resonance imaging brain lesions. CONCLUSION: This case report suggests that extra-cranial vasculitis and dysplasia can exceptionally be found in patients satisfying cerebral amyloid angiopathy–related inflammation criteria.