Neurofibromatosis type 1 (NF1)-associated vasculopathy is usually diagnosed decades after the clinical diagnosis of NF1. Childhood NF1-associated renal artery vasculopathy or moyamoya-like brain vasculopathy could be clinically silent for a long time. We report a 12-year-old boy who had systemic hypertension found incidentally at a routine check-up. Physical examination showed caféau- lait spots and strong radial pulses. Abdominal computerized tomography angiography showed severe right ostial renal artery stenosis. Genomic study showed a heterozygous mutation c.5902C > T (p.R1968*) and two heterozygous single nucleotide polymorphisms (NCBI: SNP rs18011052 and rs2905876) of NF1 gene. After endovascular revascularization for renovascular hypertension caused by renal artery stenosis, including percutaneous transluminal renal angioplasty and stent implantation, blood pressure dropped effectively from 205/143 mmHg to 130/90 mmHg. Supine renin level dropped from 87.2 pg/ mL to 47.9 pg/mL. Unfortunately, right hemiplegia, transient visual loss with blind spots (scotomas), and clumsiness of extremities emerged insidiously 3.5 months later. Brain magnetic resonance imaging and magnetic resonance angiography showed ischemic infarction involving the watershed area of the anterior and middle cerebral arteries, indicating presence of moyamoya-like brain vasculopathy. A dilemma is that a significant decrease of blood pressure after endovascular revascularization for renal artery stenosis may have potentially unmask the moyamoya-like brain vasculopathy in this patient. Vasculopathy could be heralding childhood NF1 in the young patients without full-fledged clinical features. Endovascular revascularization for renal artery stenosis could be a double-edge sword in childhood NF1 presenting with concomitant renal and cerebral artery vasculopathy.

Keywords: moyamoya syndrome, neurofibromatosis type 1, percutaneous transluminal renal angioplasty, stent implantation, vasculopathy