A Case of Moyamoya Disease With Spontaneous Regression of Posterior Choroidal Artery Aneurysm After Improvement in Obesity and Administration of an Antihypertensive Drug.

A 24-year-old obese female (height = 162 cm, weight = 84 kg, and BMI = 32.0) developed transient dysarthria and left hemiparesis, which was diagnosed as moyamoya disease (MMD) after imaging studies. Cerebral angiography and single photon emission computed tomography studies revealed that the above symptoms were caused by hemodynamic insufficiency in the bilateral hemispheres with right-sided predominance, and a right-sided superficial temporal artery-middle cerebral artery bypass was performed. After the surgery, the patient was uneventful, but her obesity gradually worsened. Nineteen months after the bypass surgery, the MRI showed compensatory development of bilateral posterior choroidal arteries, and 29 months later, her weight was 87.9 kg and BMI was 33.5, further worsening her obesity, and the MRI showed an aneurysm formation on the right choroidal anastomosis. While considering the addition of revascularization surgery, as a result of obesity improvement (weight = 75 kg and BMI = 28.6) and blood pressure control as vascular risk management, the aneurysm spontaneously disappeared without bleeding on MRI five months after its confirmation. We report on the importance of vascular risk management in patients with MMD.