Table 2.

Summary table for carotid body tumor

Definition	Carotid body tumors, also known as paragangliomas or chemodectomas, are rare neuroendocrine neoplasms which arise near the carotid bifurcation within glomus cells.
Etiology	Derived from the embryonic neural crest.
Incidence	CBTs is 1–2 per 100,000. CBTs are rare chemical receptor tumors which accounts for 0.6% of the head and neck tumors in humans. The CBT is usually benign with the incidence of malignant tumors below 10%.
Gender ratio	Slightly higher prevalence in women than men (male-to-female ratio of 1:1.9).
Age predilection	CBT can be found at any age and is frequently seen in those between 50 and 70 years old.
Risk factors	Familial factor (31.8% of cases) accounts for a higher proportion non-familial factor (4.4% of cases).
Location	More tumors (57%) are on the right side, whereas 25% are on the left, and 17% are bilateral.
Treatment	In order to prevent local invasion and metastasis, early surgical excision is considered a primer curative treatment option for the treatment of CBTs.
Prognosis	While the majority of these tumors are benign, 2%–13% pursue a malignant course with metastases to regional lymph nodes, lungs, and bones.
Findings on imaging	-Ultrasound: These tumors are characteristically a well-defined hypoechoic mass that splays the carotid bifurcation. With color Doppler imaging, a hypervascular, low-resistance flow pattern is evident. -CT-Scan: Mass with soft tissue density on non-contrast CT images. The lesion shows heterogeneous enhancement at the carotid bifurcation in the early arterial phase on contrast-enhanced CT images. It has bright and rapid enhancement. -MRI: On T1-weighted images, the lesions are iso to hypointense compared to muscle. They have intense enhancement following gadolinium administration. On T2-weighted images, they are hyperintense compare to muscle. DWI shows evidence of restricted diffusion along with the ADC map. Typical lesions show signs of “salt and pepper” appearance. -Angiography: Splaying of the carotid vessels is identified with an intense blush in tumor with an “early vein” seen due to arteriovenous shunting. The ascending pharyngeal artery is the main contributing supply. -Scintigraphy: Although not specific, shows uptake with metaiodobenzylguanidine and octreoscan scintigraphy and can be useful for assessing multiple lesions.