They presents as asymptomatic palpable neck mass in the anterior triangle of the neck, slow-growing tumours remaining asymptomatic for many years, vertically fixed because of its attachment to the bifurcation of the common carotid (Fontaine sign). A bruit can be felt, however, the absence of a bruit does not rule out a carotid body tumor. 10% of the patients may present with pain, hoarseness, dysphagia, Horner syndrome or shoulder drop due to involvement of hypoglossal, glossopharyngeal, recurrent laryngeal or spinal accessory nerve or involvement of the sympathetic chain. When CBTs are functional, symptoms similar to those of pheochromocytoma. such as paroxysmal hypertension, palpitations and diaphoresis, are seen. To rule out functional carotid tumours, urinary catecholamines, vanillylmandelic acid (VMA), and metanephrines should be estimated. Although ultrasonography is good enough for initial diagnosis, CT scan is helpful and typically reveals a hypervascular tumor located at carotid bifurcation. MRI imaging is considered to be the gold standard and shows characteristic salt and pepper appearance on T1-weighted image. MRA provides better insight into the vascularity of the tumour and its feeder vessels.

Accurate diagnosis is usually based on angiographic criteria, which show the typical LYRE sign. Angiography is also helpful in high-risk tumours (Shamblin II or III) that need either embolization or a preoperative balloon occlusion test. Biopsy of carotid body tumors  is not indicated. Histologically CBTs are classified into noninvasive, locally invasive, and metastatic types. Unfortunately, malignancy cannot be detected by routine histological findings and is only defined when the tumour metastasizes to regional lymph nodes or more distant sites.