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Background: Fibromuscular dysplasia (FMD) can cause cerebral aneurysms and dissection, which can lead to stroke. Angiographic findings are important in the diagnosis. We report a case of FMD in which the cause of hemorrhage could not be determined by angiography. Case Description: A 73-year-old woman suffered from intracerebral hemorrhage (ICH) associated with FMD without abnormal angiography cerebral vessels. She presented with headache and nausea. Subsequent head-computed tomography-revealed ICH in the left frontal lobe, and contrast-enhanced magnetic resonance imaging revealed a gadolinium-enhancing lesion in the perihematoma area and in the genu of the corpus callosum. Although cerebral angiography revealed a string of beads appearance in the bilateral extracranial internal carotid arteries, no abnormality explaining the hemorrhage was identified. The hematoma was removed and the pathological diagnosis was FMD. In the pathological specimen, various patterns of vulnerable vessels, such as aneurysmal dilatation and obstruction, were observed, which could easily collapse and result in hemorrhage. In the case of ICH of unknown origin, microscopic vessel disruption due to FMD should also be considered. Conclusion: FMD can cause ICH in microscopic vascular lesions that are undetectable on angiography.