Agenesis of the right internal carotid artery associated with ipsilateral Raeder syndrome, first case report.

Raeder's syndrome is characterized by pain, ipsilateral oculosympathetic defect (ptosis and miosis), and ipsilateral trigeminal dysfunction. We report the first case of agenesis of the right internal carotid artery, which presented with a third-order postganglionic oculosympathetic paralysis and a dysfunction of the ophthalmic division of the trigeminal cranial nerve. An MRI angiography was performed and revealed a total absence of flow in the right internal carotid artery with a permeable right Sylvian artery through a well-developed right posterior communicating artery. A CT of the skull base revealed a total absence of the right carotid channel, which was consistent with a congenital absence of the right internal carotid artery.