Intracranial dissecting and giant serpentine aneurysms are rare vascular anomalies. Their precise cause has not yet been completely clarified, and the radiological appearance of such lesions can be different in each case according to the effect of hemodynamic stress on a pathologic vessel wall. For berry aneurysms, available evidence overwhelmingly favors their causation by hemodynamically induced degenerative vascular disease and there is an obvious need to determine the hemodynamic parameters most likely to induce the precursor atrophic lesions. In this study, a case of a giant dissecting aneurysm angiographically mimicking serpentine aneurysm of the right ophthalmic artery is reported and the relevant literature is reviewed to investigate the pathological characteristics and pathogenesis of this lesion. In the present case, radiological investigation of the lesion suggested a serpentine aneurysm, but the diagnosis was corrected to dissecting aneurysm subsequent to the pathological examination of the resected aneurysm.