Isolated intracranial fibromuscular dysplasia of the posterior cerebral artery.

•Isolated intracranial FMD with the “string of beads” appearance is very rare.•In young patients without the risk of atherosclerosis, intracranial FMD should be considered as a pathophysiology of stroke.•TOF-MRA may show unclear “string of beads” appearance such as segmental luminal irregularities in intracranial FMD.