A traumatic superficial temporal artery aneurysm after a bicycle accident

Abstract

INTRODUCTION

Traumatic aneurysm of the superficial temporal artery (STA) was first described in the 17th century, after a blunt head trauma [1]. Since then approximately 200 cases have been reported. This has been thoroughly described by van Uden et al. in 2011 [2]. The STA is one of the terminal branches of the external carotid artery, which supplies blood to the scalp [1–3]. Owing to its superficial and anatomical course, the STA is vulnerable to blunt head trauma, which can eventually result in traumatic aneurysms of the STA after a few weeks [4–7]. At the daily routine, physicians are often encountered with patients with swellings on the scalp. Most often these were diagnosed as simple sebaceous cysts, epidermoid cysts, pilar cysts, lipomas and in case of a history of trauma as hematomas. Traumatic aneurysms of the STA should be a differential diagnostic consideration in patients with a history of trauma and a swelling on their scalp as is prompted in this report.

CASE REPORT

A 50-year-old healthy man presented with a lump on the temporal side of his head. Six weeks before, he fell off his mountain bike, hitting the ground with the left side of his head while wearing a helmet. Initially, there were no signs of injury, but after a few weeks a progressive painless lump has appeared at the place where his head smashed into the helmet at the time of the accident. Physical examination revealed a smooth lump, measuring 1 cm with no signs of inflammation or tenderness (Fig. 1). Ultrasonography showed a dilated vessel with a minor defect of the luminal wall. Our patient was treated by excision of the swelling, which turned out to be an aneurysm of the STA (Fig. 2). The diagnosis was reconfirmed in the pathological report. The patient recovered uneventfully.

Figure 1:

Clinical presentation of a lump on the scalp with a diameter of 1 cm.

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Figure 2:

Operative image of a STA aneurysm.

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DISCUSSION

About 95% of the aneurysms of the STA have a traumatic cause, mostly as a result of blunt head trauma. The remaining 5% of the cases are considered spontaneous aneurysms from congenital or atherosclerotic origin [3]. An aneurysm of the STA may be present as painless, pulsatile masses at the site of the injured arterial branch and could be associated with a palpable thrill [8]. Our case demonstrates that signs of injury can be absent at the time of the accident, but STA aneurysms may still develop a few weeks after the trauma has occurred. Duplex ultrasonography is a reliable and safe method to confirm the diagnosis [4]. In cases where STA aneurysms are left untreated, cosmetic concerns, headaches and more importantly ruptures of the aneurysm have been reported [2, 9].

Surgical resection of the aneurysm is the treatment of choice in most reports. Endovascular treatment modalities such as thrombin injection and catheter-based embolization have been described in a few cases [2]. These techniques can be used in selected cases in which surgery is not possible or not preferred for cosmetic reasons. Thrombin injections show an average success rate of 80%. Possible disadvantages of the endovascular treatment options could be a persisting lump or embolic complications of the carotid artery. After failure of the thrombin injections, a second injection was needed or surgery in a second stage [2].

Although a scar comes along with surgery, exploration with ligation and excision is considered as a safe and definitive treatment of aneurysms of the STA [4]. In conclusion, physicians should be aware of traumatic aneurysms of the STA in patients with a history of trauma and a swelling on their head.

CONFLICT OF INTEREST STATEMENT

None declared.

REFERENCES