Carotid agenesis with intercavernous anastomosis

Area of Science:

• Neurology
• Vascular Neurology
• Neuroimaging

Background:

• Agenesis of the internal carotid artery (ICA) is a rare congenital condition.
• Abnormal arterial communications, such as intercavernous anastomoses, are exceptionally uncommon in conjunction with ICA agenesis.

Observation:

• A middle-aged woman presented with sudden, severe holocranial headache.
• CT scan diagnosed subarachnoid hemorrhage.
• Digital Subtraction Angiography revealed complete absence of the right internal carotid artery.

Findings:

• The right middle cerebral artery was supplied by an incidental intercavernous anastomosis originating from the left internal carotid artery.
• No aneurysms, arteriovenous malformations, or other vascular abnormalities were identified.
• The patient was managed conservatively for the subarachnoid hemorrhage.

Implications:

• This case underscores the importance of comprehensive vascular imaging in diagnosing rare cerebrovascular anomalies.
• Understanding such rare anatomical variations is crucial for accurate diagnosis and management of neurological emergencies.
• Conservative management was successful in this unique presentation of subarachnoid hemorrhage secondary to an intercavernous anastomosis in the absence of a right ICA.