Sirs:Syncope is a common and potentially dangerous symptom with interdisciplinary differential diagnosis. Frequently, it is not possible to achieve an obvious distinction between neurologic and cardiovascular causes, and the underlying mechanism for syncope often is not established. In cases of recurrent unexplained syncope, despite intensive testing, it may be reasonable to consider even rare differential diagnosis [1][2][3]. We report the case of a patient with paraganglioma of glomus caroticum, who had suffered from recurrent syncope as the major symptom.A 39-year-old woman without known cardiovascular risk factors and a normal state of health was referred to our cardiology department to get a second opinion medical examination of her repeated episodes of syncope.Approximately 4 months ago she had suffered from the first of five syncopal spells. A typical episode was characterized by sudden onset of dizziness, followed by a temporary loss of consciousness. The syncopal episode lasted a few seconds to minutes and did not include any seizure-like symptoms. It was not related to any particular movement of the head, to micturition, or to any specific activity. There was no relevant family history of disease. The patient was taking levothyroxine 100 lg, due to a subclinical hypothyroidism which is because of Hashimoto's thyroiditis.Prior to the admission to our department, several investigations already had been carried out. Electrocardiography, echocardiography, Holter monitoring, and electro-encephalography had demonstrated normal findings.Arrhythmias, orthostatic hypotension, or an abnormality of blood chemical levels had not been reported and all tested functions in the neurological examination were within normal ranges.A bilateral Doppler ultrasound showed normal perfusion of the common carotid artery, internal carotid artery, and external carotid artery. Interestingly, an enlarged lateral lymph gland in the region of the left carotid bifurcation was described, but referring to this finding no further diagnostic was carried out.Magnetic resonance imaging of the brain revealed a left-sided temporo-basal arachnoid cyst of 4 cm in diameter with dysplasia of the surrounding temporal lobe. During carotid sinus massage and head-turning, with continuous electrocardiographic and blood pressure monitoring, neither bradycardia nor asystole allegedly could be provoked. A positive result to tilt testing was classified as neurocardiogenic syncope (cardioinhibition without asystole). Due to the positive result to tilt testing and low blood pressure, a sympathomimetic medication with midodrine was recommended.Despite this medication, the symptoms persisted in the following weeks. Therefore, several additional out-patient investigations (orthopedic, psychosomatic) were performed without new consolidated findings.On examination after admission to our department, Doppler ultrasound revealed a 2.3 9 1.9 cm solid mass with a high degree of vascularization in the region of the left carotid artery bifurcation, causing carotid arter...