A woman aged 68 years came to primary care dermatology outpatients requesting excision of a lesion situated over her right clavicle. The lesion had been present for more than 15 years but had recently increased in size. Physical examination revealed a pedunculated exophytic tumor measuring 13mm in diameter. It had a violaceous color and a vascular appearance, and telangiectasias were observed peripherally (Fig. 1). On palpation, the mass was pulsatile. Echo-Doppler showed the mass to be an elongation of the common carotid artery in the form of a loop, suggesting arteriovenous angiodysplasia. Magnetic resonance angiography with contrast confirmed that this was a high-flow vascular lesion (Fig. 2). The lesion was excised under local anesthesia.

Figure 1

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Figure 2

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Arteriovenous malformations or angiodysplasias arise as a result of errors in vascular morphogenesis; such lesions are very rare in the common carotid artery. The majority are congenital, but they can also develop after surgical procedures such as stent placement in the artery. Meticulous physical examination including inspection and palpation is essential to avoid diagnostic error, to decide on appropriate additional tests, and to determine the most suitable treatment.