Congenital Absence of the ICA with Previously Undescribed Anomalous Suprasellar Internal Carotid Communication

We present a previously undescribed case of the absence of the left ICA with an anomalous suprasellar collateral artery arising from the ophthalmic segment of the right ICA and supplying the supraclinoid segment of the left ICA. Congenital absence of the ICA is rare and is associated with an increased incidence of cerebral aneurysms. Recognition of all potential collateral circulation patterns is essential for treatment planning purposes.