Systemic vascular diseases such as fibromuscular dysplasia, Ehlers-Danlos syndrome, Marfan syndrome, and Behçet's disease are known to cause spontaneous dissecting aneurysms of the cervical internal carotid artery. These diseases are generally associated with vascular fragility; therefore, invasive treatments are avoided in many cases of dissecting aneurysms, and a conservative approach is used for the primary disease. Surgical or intravascular treatment may be chosen when aneurysms are progressive or are associated with a high risk of hemorrhage; however, there is no consensus on which treatment is better. We report a case of a dissecting aneurysm of the cervical internal carotid artery in a patient with suspected Behçet's disease, which was treated using stent-assisted coil embolization. A man in his 40's, with suspected Behçet's disease, presented with an enlarged dissecting aneurysm of the right cervical internal carotid artery. The lesion was present for approximately 10 years. We performed stent-assisted coil embolization for the lesion. Post-surgery, no aneurysms were detected with carotid artery echography. Our case report suggests that stent-assisted coil embolization is a promising treatment for dissecting aneurysms of the cervical internal carotid artery. In addition, the procedure demonstrates the utility of carotid artery echograms for examining recanalization after stent-assisted coil embolization.