A pulsating subcutaneous preauricular mass in a 80-year-old female patient

80-year-old woman was referred to ultrasound (US) examination due to right-sided preauricular painless pulsating mass, increasing in size during last two years. No history of surgery or trauma in right temporal area. Physical examination: pulsating, ball-shaped mass in right preauricular area, 2 cm in diameter. No tenderness during palpation.

An US examination revealed an anechoic (cystic) mass, measuring 1.5 cm in diameter, with a mural thrombus apparent at the lateral wall. Color-Doppler Flow Imaging (CDFI) demonstrated continuity with the main trunk of superficial temporal artery (STA) and displayed a turbulent flow inside the lesion.

A computed tomography (CT) angiography was also performed, confirming that the preauricular mass was a saccular aneurysm of the main trunk of STA, measuring 1.4 cm in diameter. A saccular aneurysm of anterior communicating artery (ACoA), measuring 0.3 cm in diameter, and a saccular aneurysm of M2 segment of left middle cerebral artery (MCA), measuring 0.4 cm in diameter, were also apparent on CT angiography. No other aneurysms or arteriovenous malformations were detected.

Background

Aneurysm of STA is a rare clinical entity, most of the cases in fact being pseudoaneurysms resulting from trauma, infection or surgery in temporal area, while true aneurysms are extremely uncommon [1–4].  The aetiology of a pseudoaneurysm includes damage to arterial wall, while in true aneurysms there is arterial wall weakness, probably congenital in nature, or a result of atherosclerotic changes [1,4]. This leads to different appearance on histopathological examination; while the wall of a pseudoaneurysm lacks media, in a true aneurysm arterial wall, consists of all three layers[5]. Indications for surgical treatment include pain, rapidly increasing size, cosmetic reasons and impact on adjacent structures [3].

 Clinical Perspective

This was a common presentation of STA aneurysm as a compressible, pulsatile mass in temporal area. Imaging was obtained to confirm the diagnosis, as well as to establish the presence of possible intracranial pathology and to plan therapeutic options accordingly. Although conservative treatment is possible, some authors do not recommend it due to possible discomfort and complications, including rupture and bleeding [3,4]. Treatment options include surgical ligation of proximal STA and distal branches and excision of the aneurysm or endovascular intervention with embolization of the aneurysm.

 Imaging Perspective

Although clinical examination and US are often enough to establish the diagnosis, CT angiography provides the most information about the anatomy of aneurysm, as well as information about potential associated intracranial pathology [4].

Outcome

No neurosurgical treatment was indicated, considering small size of detected intracranial aneurysms. However, due to progressive growth of the STA aneurysm, risk of rupture and bone erosion, surgical removal was recommended. Patient underwent surgical excision under general anaesthesia. The proximal STA and distal branches were ligated and the aneurysm was dissected from the surrounding tissues. Histopathological analysis confirmed an aneurysm of the STA, containing all three layers of arterial wall. A mural thrombus with in-growth of fibroblasts was also demonstrated. The findings were concurrent with a true saccular aneurysm of STA.

Teaching points

True aneurysm of STA is a rare entity, usually presenting as a pulsatile mass, sometimes causing a headache in the temporal region. Patients present with no history of trauma.

Pseudoaneurysms of STA are more common, usually following trauma to temporal area.

Clinical examination and Doppler US suffice for the diagnosis, but CT angiography should be performed if associated intracranial pathology is suspected.

Surgical or endovascular treatment is indicated due to possible complications or discomfort.

Written informed patient consent for publication has been obtained.