Tuesday, April 20, 2010

Carotid Body Tumor

A carotid body tumors (CBT) are rare neoplasms, but they respresent 65% of the head and neck paragangliomas. These tumors are slow growing that can remain asymptomatic for years. These tumors develop at the medial aspect of the carotid bifurcation. It is a small, reddish-brown, oval structure. A healthy gland measures 3 to 5 mm in diameter and weighs less than 15 mg on average. The gland is highly vascular and receives its blood supply from the feeder vessels that are running through the Mayer ligaments, primarly from the external carotid artery. The carotid body originates in the neural crest, it is important in the bodies acute adaptation to the concentrations of oxygen, carbon dioxide, and pH. The carotid body protects the organs from hypoxic damage by releasing neurotransmitters that increase the ventilatory rate when stimulated. There are three different types of carotid body tumors and those are: familial, sporadic, and hyperplastic. The familial form is most common in younger patients , 10 to 50%. The sporadic form is the most common type, it is approximately 85% of carotid body tumors. The hyperplastic form is is very common in patients with chronic hypoxia, which includes patients that live at high altitudes. A carotid body tumor can occur in children, but also CBT's are considered to be a disease of the middle age. About 5% of CBT's are bilateral and 5 to 10% are malignant, but these rates are much higher in the patients with inherited disease. It is stated that familial tumors are found to be 5.8 times more common in patients who have had carotid body tumors as compared with patients who have paragangliomas at other sites. Patients with chronic hypoxic conditions, such as the patients that live at higher altitudes or those who have COPD, or cyanotic heart problems. This can be too much for the carotid bodies, and lead to hypertrophy, hyperplasia, and neoplasia of the cells. Approximately 10% of cases that are present with cranial nerve palsy with paralysis of the hypoglossal, glossopharyngeal, recurrent laryngeal, spinal accessory nerve, or the involvement of the sympathetic chain. CBT's can be associated with pain, dysphagia, shoulder drop, Horner syndrome, and hoarseness. As the tumor gets larger and compresses on the carotid artery, and on the surrounding nerves. Other symptoms may occur such as: pain, tongue paresis, hoarseness, Horner syndrome, and dysphagia.

Chaaban, Mohamad MD. (May 2009). Carotid Body Tumor. Retreived from http://emedicine.medscape.com/article/1575155-overview

(May 2009). Carotid Body Tumor. Retreived from http://www.ajronline.org/cgi/content-nw/full/187/2/492/FIG8

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