Hemiatrophy of the tongue caused by an extensive vagus nerve schwannoma masquerading as a carotid chemodectoma.

BACKGROUND: Carotid chemodectomas or carotid body tumors are rare neoplasms, generally benign and frequently asymptomatic, which represent 0.6 % of all head and neck tumours. Schwannomas or neurilemmomas are benign, slow growing tumours that derive from the sheath of peripheral and cranial nerves. Of all neurilemmomas, 25-45 % originate from the head and neck region, with the vagus nerve being one the most encountered sites of occurrence. CASE REPORT: We describe a schwannoma originating from the vagus nerve mimicking a carotid body tumour and compromising the function of the hypoglossal nerve. DISCUSSION: Patients with lateral neck masses near the bifurcation of the carotid artery are often referred to the maxillofacial surgeon. The differential diagnosis of these lesions includes a variety of tumours among which carotid chemodectomas and vagus nerve schwannomas have a significant incidence. Both lesions may appear as completely asymptomatic, thus it is very difficult to identify the origin of the tumour based on physical examination. In making a differential diagnosis of the cervical tumours imaging studies play a key role.
PURPOSE: A diagnostic algorithm based on contemporary imaging modalities, which can be useful in order to distinguish between these two pathological entities is presented.