Pediatr Nephrol (2011) 26:2081–2084 2083 Fig. 2 Frontal view of maximum intensity projection reconstruction image of MR angiogram shows a left renal artery ostial stenosis (arrow) normal cutaneous elements, and are caused by somatic mutations producing mosaicism [6]. Most often they are linear, following the Blaschko lines, but segmental distribu- tion can be found. The term “epidermal nevus syndrome” refers to sporadic neuro-ectodermic disorders in which epidermal nevi are found in association with deformities and dysplasia of the skin, eyes, brain, skeleton, and heart. Both the cardiovascular and skeletal systems are derived from the mesoderm; thus, epidermal nevus syndrome may result not only from ectodermal, but also from mesodermal defect [7]. Bilateral renal artery stenosis is an unusual vascular malformation associated with epidermal nevus syndrome. In the literature several vascular malformations were reported: coarctation of the aorta, ventricular septal defect, pulmonary artery stenosis, azygos anterior cerebral artery, internal carotid artery occlusion, bilateral vertebral artery occlusion, and unilateral renal artery stenosis [4, 7, 8]; bilateral renal artery stenosis has not been reported so far. However, such an abnormality has been more commonly reported in other neuro-ectodermic diseases, for example, neurofibromatosis type 1, in which renal artery stenosis can be detected in 61.5% of patients [9]. In our patient, the MRA should have been performed earlier to search for another cause of the secondary hypertension in addition to the mild coarctation of the aorta, since blood pressure was not controlled by medical treatment prior to surgery. Although conventional arteriog- raphy could have been more informative than MRA, this might be done later if the situation changes. As the renin–angiotensin–aldosterone system (RAS) is often activated in patients with renal artery stenosis, our patient had been treated with a regimen including ACE inhibitor and beta-blocker. Although RAS inhibition may induce acute renal failure in some patients with bilateral renal artery stenosis or high-grade stenosis in one kidney, the probability of such a complication appeared to be low, and in most cases, it was reversible with discontinuation of treatment [10]. A percutaneous transluminal angioplasty was not attempted because of known poor results in other neuro- ectodermic diseases such as neurofibromatosis, and also because of bilateral involvement with a risk of thrombosis and further renal damage compared with acceptable control of blood pressure by medical therapy [11]. The overall therapeutic attitude was made with the motto “primum non nocere” as long as the situation is stable for several years. Advice was gathered from local experts to make the final decision, which was a consensus among nephrologists, vascular surgeons, and radiologists in addi- tion to the approval and support of the parents. The optimal treatment strategy for renal artery stenosis remains unclear. There are no randomized clinical trials comparing the effects of angioplasty stenting versus medical therapy alone in such patients with vascular dysplasia. In fact this technique had been attempted in a patient with epidermal nevus syndrome and unilateral renal artery stenosis and failed because of the rigidity of the stenotic lesion [5]. According to the guidelines of the Society of Nuclear Medicine and the European Association of Nuclear Med- icine, the DMSA scan is not indicated for our patient in the absence of clinical, biological or radiological signs of renal function impairment or deterioration, although it would have been of great value if it had been done earlier as a baseline for renal function evaluation and follow-up. Fig. 3 Axial–oblique view of maximum intensity projection recon- struction image of MR angiogram shows a right renal artery ostial stenosis (arrow)