Neurofibromatosis 1 vasculopathy manifesting as a peripheral aneurysm in an adolescent

Arterial vasculopathy is a well-recognized but uncommon manifestation of neurofibromatosis type 1 (NF-1). It can manifest as stenoses, aneurysms or arteriovenous malformations. NF-1 vasculopathy typically involves the aorta, visceral arteries or carotid-vertebral circulation. Aortic and visceral vasculopathy typically presents as stenotic lesions, while aneurysms have been reported primarily in the subclavian/vertebral arteries. Aneurysms of the peripheral/extremity arteries are an extremely rare complication of NF-1 that may present as a mass or spontaneous rupture. We present the case of a teenage boy with an arm mass secondary to an aneurysm. We hope this case will increase recognition of the variable clinical manifestations of NF-1 vasculopathy among radiologists.