Clinical vignette:
A 29-year-old female presented after she lost consciousness and fell while walking. Syncope was preceded by 15 minutes of flushing, nausea and palpitations. She reports similar episodes in preceding months. Assessment included normal vital signs, electrocardiogram, echocardiogram, thyroid function, CBC, and CMP. Head/neck CT revealed bilateral carotid body tumors (Fig 1). Her father has bilateral carotid body tumors which were never evaluated. Plasma and urine metanephrines were normal.
The carotid body tumor was excised. Pathology confirmed a paraganglioma with positive synaptophysin (Fig 2a) and chromogranin (Fig 2b) stains. Genetic testing revealed a succinate-dehydrogenase-complex subunit D gene mutation, associated with hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndromes which commonly found in the carotid body. They usually arise from the autonomic nervous system anywhere from the skull base to the pelvis with an incidence of 1:30,000-1:100,000 (1). About 95% of head and neck paragangliomas are non-secretory (2). Symptoms can arise from catecholamine hypersecretion, presenting as hypertension, headaches, diaphoresis, flushing, anxiety or palpitations, and can be episodic or sustained, or mass effect. Treatment is resection of the tumor(s) with alpha-adrenergic blockade pre-operatively, however observation is reasonable for non-secretory, asymptomatic tumors. Patients and first-degree relatives should be screened with biochemical testing and imaging.