Non-bifurcating cervical carotid artery with ipsilateral internal carotid artery hypoplasia.

PURPOSE: A non-bifurcating cervical carotid artery (NBCCA) is a rare anomaly. Hypoplasia of the internal carotid artery (ICA) is also rare. To the best of our knowledge, their simultaneous coexistence has not been previously reported. METHODS: We report a case of NBCCA associated with ipsilateral ICA hypoplasia diagnosed by magnetic resonance angiography (MRA). RESULTS: A 52-year-old woman was transported to our hospital by ambulance with severe headache. Magnetic resonance imaging revealed a large suprasellar mass. MRA showed impaired delineation of the right ICA and a 2-mm left ICA aneurysm. Extracranial MRA revealed a right NBCCA. Computed tomography showed a narrow right carotid canal. Right NBCCA concomitant with congenital hypoplasia of the ipsilateral ICA was diagnosed. CONCLUSION: Careful imaging assessment is important to identify these rare anatomical variants and associated aneurysms on the collateral pathway. Awareness of such variations is important in clinical practice, particularly for imaging interpretation and procedural planning.