Spontaneous intra-parotid pseudoaneurysm of the external carotid artery.

INTRODUCTION: The authors report a case of spontaneous intra-parotid pseudoaneurysm of the external carotid artery, never previously described in the literature.

CASE REPORT: A 59-year-old woman presented with a palpable, non-pulsatile, 2 cm retromandibular left parotid mass with no triggering factors. This mass was considered to be a mixed tumour, although it did not present the typical features on MRI. At surgery, the lesion in the lower pole of the parotid gland was found to be pulsatile, in favour of pseudoaneurysm of the external carotid artery. The external carotid artery was ligated to remove the lesion. Definitive histological examination confirmed the diagnosis of pseudoaneurysm.

DISCUSSION: Pseudoaneurysms of extracranial arteries are rare, most commonly involve the internal carotid artery and are essentially secondary to trauma. Review of MRI images demonstrated hyperintense arterial blood flow within the hypointense mass on T2-weighted sequences. The presence of this sign must therefore be investigated in the context of atypical images of a parotid mass. Although rare, and despite the absence of trauma, the diagnosis of pseudoaneurysm of the external carotid artery or one of its branches should therefore be considered in the presence of an atypical parotid mass.