Extracranial Internal carotid artery aneurysm presenting with dysphagia and dysphonia.


M A Nusrath, S Mishra, A W Paterson, A K Robson.
Department of Oral & Maxillofacial Surgery,
Department of Otolarngology.
Cumberland Royal Infirmary.
Carlisle. UK.

Correspondance to:
M A Nusrath, MBChB,MRCS( Glasg),FDSRCS,FDSRCPS(Glasg)
Specialist Registrar in Oral & Maxillofacial Surgery,
Cumberland Royal Infirmary,
UK.
manusrath@yahoo.com

Abstract:
Extra cranial aneurysms of the internal carotid artery are extremely rare. We report a case of an extracranial internal carotid aneurysm in a 71 year old lady who presented with a right parapharyngeal mass with longstanding symptoms of dysphagia and dysphonia. The importance of MRI/CT to establish a radiological diagnosis before fine needle aspiration cytology or open biopsy of such masses is highlighted.

Key Words:
Internal carotid artery, aneurysm, parapharyngeal mass.

Introduction:
Extracranial aneurysms of the internal carotid artery are rare. They may present with a mass in the oropharynx or in the neck. Small aneurysm may remain asymptomatic. Large aneurysms may present with pressure effects which may result in cranial nerve palsies. We report a case of fusiform extracranial internal carotid artery aneurysm (ECICA).
Case Report:
A 71 year old lady was referred with a one year history of sore throats, upper respiratory tract infections, foreign body sensation at the back of her mouth and occasional hoarseness of voice. She was normotensive with a history of diverticular disease and hypercholesterolemia. Clinical examination revealed asymmetry of the right tonsillar area with the tonsil being pushed medially.
A parapharyngeal mass was suspected. Flexible nasoendoscopy of the larynx was unremarkable. No pulsations were visible. A MRI scan was arranged which revealed a large right extracranial internal carotid aneurysm (ECICA) (fig 1). A CT angio of the aortic arch, carotid artery and circle of Willis confirmed a 27 mm diameter fusiform aneurysm of the right ECICA 3 cm from the carotid bifurcation with minor calcifications in the aneurysm wall (Fig 2). The contra lateral carotids, circle of Willis and aortic arch did not show any pathology. She was subsequently referred to the interventional radiologists for an endovascular stent.

Fig 1. Axial MRI showing an enlarged right internal carotid artery

 

Fig 2. CT angiogram showing the extent of the internal carotid artery aneurysm.

 

Discussion:
Aneurysms of the extracranial carotid artery system are very rare. They are usually caused by atherosclerosis, trauma, infections of the parapharyngeal space, dysplasia and mycotic infections.7 Aneurysms of the ECICA have been classified into five clinical types: fusiform, saccular, spontaneous dissecting, mycotic and pseudo aneurysms. Only 41 of 1118 aneurysms in a study of the peripheral arteries arose from the extracranial carotid artery system8.
Large carotid artery aneursyms may present as a visible/palpable mass in the cervical region near the angle of the mandible or intra orally in the parapharyngeal space as a pharyngeal or tonsillar mass and can be mistaken for a peritonsillar abscess or a neoplastic lesion of the tonsil or the parapharyngeal space. Although some of the aneurysms may be pulsatile this sign may be absent. The patients may present with transient ischemic attacks and stroke. Symptoms include foreign body sensation, dysphagia as in this case. Syncope with glossopharyngeal pain9, Hypoglossal, glossopharyngeal nerve palsies10, recurrent laryngeal nerve involvement with vocal cord palsy11, vagus nerve palsies and cervical sympathetic chain involvement with horners syndrome have also been reported12.
Masses of the parapharyngeal space can be divided into lesions of prestyloid and poststyloid compartment. This delineation can usually be done with the help of a MRI scan. The prestyloid contains within it the deep lobe of the parotid gland, adipose tissue, lymph nodes of the deep parotid gland. Tumours of deep lobe of parotid gland commonly present in the prestyloid region.
The poststyloid compartment contains the internal carotid artery, internal jugular vein, cranial nerves IX-XII, sympathetic chain and lymph nodes. Neurogenic tumours are common in this compartment. This differentiation is important as it can help in the differential diagnosis along with the potential surgical approaches for removal of the tumour.
Anteromedial displacement of the carotid sheath structures occur in tumours of the poststyloid compartment whereas posteromedial displacement occurs in the tumours of the prestyloid compartment. Although the diagnosis of an aneurysm may be apparent right from the outset with a pulsatile mass, it may not always be the case. Aneurysms of the carotid artery should be considered in the differential diagnosis of a parapharyngeal mass. These lesions may mimic a neck or tonsillar abscess. Fine needle aspiration or Incisional biopsy of the mass may lead to disastrous consequences. Quinsy usually has a short history of swelling usually 3-10 days with systemic symptoms like pyrexia and trismus.

This case illustrates the importance of a thorough Head & Neck examination along with the use of imaging in the form of MRI,CT scans or duplex ultrasonography before fine needle aspiration cytology or Incisional biopsies of parapharyngeal masses are carried out.

References:
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