Infundibular origin of a duplicated anterior communicating artery mimicking an aneurysm

The anterior communicating artery (AComA) is a common site of morphological variation and aneurysm formation. We report an unusual vascular anomaly identified during routine 3T magnetic resonance angiography (MRA) in a 67-year-old male under evaluation for cerebrovascular disease. Imaging revealed a duplicated AComA, with the first segment originating from an infundibular dilation of the right anterior cerebral artery (ACA). A second, extremely short AComA segment, 0.9 mm, was located distally. Although infundibular dilations are typically benign, they warrant careful evaluation due to their potential to mimic aneurysms and possibly contribute to aneurysm development. Accurate identification using high-resolution imaging techniques is essential to prevent misdiagnosis and to inform appropriate clinical management. This case highlights the importance of recognizing rare vascular variants, particularly in preoperative planning and differential diagnosis.